2524: gum Nov 10, 2021

Although the term for the product of the resin is 'rubber' in English, the resin itself is known as 'gum'. This is from Ancient Egyptian qmyt (resin; gum), also related to qmy (oil). This was the source of many related European words thanks to its adoption into Ancient Greek and Latin which begot many terms, but also Semitic terms like Hebrew גומי (gumi) and Aramaic גמי (gami), and via Greek קומא‎ (quma), with the later being specific to acacia. On the other hand, 'rubber' is just from the material's association to erasers, and another term, 'caoutchouc' is from Nahuatl, but only refers to unvulcanized rubber.

2523: Mysterious Origins of Diego Nov 9, 2021

The Spanish name Santiago is from an earlier Sant Yago, but in English this is the name of Saint James. The discrepancy in the name goes even further, since in Hebrew the name is יעקב (Yaaqov). That said, it is not certain by any means that what was once thought to be the successor to 'Yago', namely 'Diego' is in fact descended from יעקב (Yaaqov) even though this would definitely not be the most radical shift over the years. Instead, the current theory is that this is from 'Didacus', itself from the Greek Διάδοχος (Diadochos) meaning 'heir; successor', though the shift in vowels from that to 'Diego' is not explained. What is certain is that 'Díaz' and its variations are just the patronymic form of 'Diego'.

2522: mesmerism Nov 8, 2021

The word 'mesmerize' now just generally refers to something that's dazzling and captivating, but 'mesmerism' was once a description of a medical procedure and (erroneous) scientific theory. Franz Anton Mesmer believed in something called 'animal magnetism'—an invisible force with physical effects—using magnets along with psychological tricks to supposedly cure people of ailments. This did actually work, but rather than being from magnetism, it was hypnosis. The salvageable procedures influenced many fields including modern talk-therapy, but the colloquial term 'mesmerize' is named from someone who may not have really known what he was doing.

2521: abacus Nov 7, 2021

The word 'abacus' came to English from Latin hence the plural 'abaci', but this word might really have a semitic origin. While now the term is used exclusively to refer to the mathematical instrument, it used to be more generic, denoting many types of boards including board-game boards and sand tables, as with the Ancient Greek ἄβαξ (ábax). This has been likened to the Hebrew אבק‎ (āvāq) meaning 'dust' which would explain the senses of the Catalan 'àbac' meaning both 'mathematical table' and 'board covered in sand'.

2520: Koppa Ϙ/ϙ Nov 6, 2021

The Phoenician abjad, which is the origin of the Greek alphabet, contained certain letters for sounds that in Greek didn't exist. The Phoenician qoph (pronounced [q]) didn't exist in Greek, and since Greek could already use Κ (kappa) the Greek letter koppa (Ϙ, ϙ) was used before back-vowels. This practice was retained in Etruscan and Italic languages for a while, but unlike Q, which also came from this same Phoenician letter, Ϙ in Greek didn't survive, except sometimes for numerical purposes to represent 90. It is a similar story with the Cyrillic koppa (Ҁ ҁ) which is also now archaic.

2519: Germanic Stress Rule: Morae & Dreimorengesetz Nov 5, 2021

While the penultimate stress rule describes the stress accent for Latin, a similar rule for Germanic languages was proposed, called Dreimorengesetz (three-mora rule), wherein the stress is placed 3 morae before the end of each word; a mora is a unit for which a light syllable (generally a short one) is one mora and a heavy syllable (generally a long one) is two morae. This has its own problems, especially in the way it necessitates categorizing the final syllable as always light, but it does provide somewhat of a sense of Germanic languages' stress.

2518: Penultimate Stress Rule Nov 4, 2021

Languages often have inbuilt rules for how each word will take stress, such as Finnish or Proto-Italic were stress is indefinitely on the first syllable, but other times it is dependant on other factors in the environment. Even in Classical Latin, which is slightly more standard, the penultimate stress rule states that if the penultimate syllable is naturally long or if it ends with a consonant it will have the stress accent, and otherwise the stress accent falls on the third-to-last syllable. There are some exceptions, especially around sounds that have been elided or historically syncopated (or of course, doesn't have enough syllables), but this will cover the vast majority of Latin words, and words of other languages.

2517: mentor Nov 3, 2021

Although the word 'mentor' is from Ancient Greek, it only started to be used as a word in the 18th century. Instead, this word comes from the name of a character Μέντωρ (Mentor) in Homer's Odyssey, namely the adviser of Telemachus. That said, the root of this word is connected to the idea itself, and related to the English 'mind', Latin 'monitor', and Sanskrit मन्तृ (mantṛ). So, while it is technically from a name, the name was given presumably due to who the character was.

2516: Rhotacism & Dissimilation Nov 2, 2021

The word 'meridian' in English, or more directly even 'ante/post meridiem' (a.m./p.m.) is from the Latin word 'merīdiēs' meaning 'midday; noon'. This is from a corrupted phrase 'medīdiēs' which is just an contraction of 'medius' (middle) and 'diēs' (day). The R in the middle of 'merīdiēs' therefore is a bit odd at first glance. In fact, this is a fairly normal occurrence of rhotacism in the transition into Classical Latin. This normally happens to the sounds [s] or [z]—not [d]—that they should turn into [r] and really this is a process of dissimilation because it is followed by another [d].

2515: A Shift in Latin 3rd Person Endings Nov 1, 2021

In Latin, the present tense, 3rd person endings are singular '-t' and plural '-unt'. In Proto-Italic however, these were featured an [i] at the end, i.e. '-ti' and '-unti' respectively, though not always spelt that way specifically. This was probably related to the way that Greek constructed its verbs, though it did eventually drop off. There are inscriptions in Pompeii however that show 'estē' for what would be the Classical Latin 'est'. Indeed, Pompeii is a great source for popular writing as opposed to more formal, high-register, and perhaps most importantly edited writing. This alternate form might have been the source for Romanian's verb endings which look like that today somewhat.

2514: calcium & calculus Oct 31, 2021

The words 'calcium' and 'calculus' are related by the common root of 'calx', or translated from Latin, 'limestone'. This makes a certain amount of sense for calcium, since this is an element and is found physically in limestone and even now is another term for kidney-stones, but the association to mathematics is not as clear. This is because the diminutive form of 'calx' took the suffix '-ulus', resulting in 'calculus' meaning 'pebble', which again doesn't seem to relate to math, but is a reference to the stones used as counters on an abacus. Before differential calculus took the more specific definition used today, 'calculus' could just mean 'to calculate', hence the relation there as well.

2514: R Rotunda: ꝛ Oct 30, 2021

There are numerous examples of pairs of letters that get combined into one ligature, which does happen even today. In a sense, that is how the German ß was formed from <S> and <Z>, but as in that case, it's only a specific pair. For a time, a form of writing lower case <r> existed known as the R rotunda which looked like <ꝛ>, and, lacking a line on the left, would be tacked on to letters only if one such like existed, like <d> or even curved lines like after <o>. This was especially used for blackletter, or in other words, the font most associated with the Middle Ages. This helped to develop the modern cursive form of <r> which is notably different to its upper-case or printed counterparts. Indeed, blackletter has some characters which, without prior knowledge, would not be interpretable to a reader today, but this case was notable since there was another form of the letter used for when there was no other letter to apply the r rotunda onto. Because this character was not popular outside blackletter fonts, it more or less fell by the wayside in the 16th century with the overall decline of the script.

2513: I Longum: ꟾ Oct 29, 2021

Latin vowels used to be written with apexes, which looked more like traditional accent mark than the macrons used for writing out long vowels in Latin today. This was the only form of punctuation, if it can even be called that, sine historically Latin had no lower-case, no spaces words or breaks for sentences. The only other variable in this system was 'i longum' or 'long i', written as ꟾ which represented the long vowel but didn't take the accent mark. While it is true that J developed from I, it is more accurate to say that J developed from ꟾ. Moreover, in Latin orthography, if two i's would be written together, the second would be ꟾ to distinguish it from N or even U (V). Likewise, in Dutch, there is a common digraph for the long [iː] sound written as IJ, and often further stylized with a smaller i in front, sometimes written as Y, though the Y was not related historically.

2512: serology and truth serums Oct 28, 2021

Serology is the study of blood, and especially pathogens in blood, but its etymology has nothing to do with that really. In Latin, 'serum'—which also led to the the English word 'serum'—which meant 'whey'. Blood has little to do with milky water, and what's more, this is related to other milky terms like Sanskrit सारण (sāraṇa) for 'buttermilk' and Ancient Greek ὁρός (horós) 'whey; curd'. This makes sense for the English 'serum', as this is a yellowish-liquid that's a component of blood. That said, 'serum' as in 'truth serum', while informal, is still a divergence from the original, presumably by association with injections generally. The association with blood in general is also an extension of the specificity of 'serum'.

2511: Common Words with Etruscan Origins Oct 27, 2021

Just because words are basic and have cognates in other, related languages, does not make the word indigenous, though it would suggest that the term is very old. For instance, 'person', 'populous' and 'military' all came to English, and many other European languages, via Latin, but these are not native Latin words. Instead, these are generally seen as having an Etruscan root, making them pre-Indo-European. 'Persona' in Latin was an actors mask, and likewise that would be in Etruscan 𐌘𐌄𐌓𐌔𐌖 (φersu), eventually replacing the native English 'wight'. 'Populus' in Latin, was thought to relate to 'plēbs' (commoner; plebeian) but the root here means 'to fill' and an Etruscan root might make more sense. 'Milēs' has a normal construction for Latin grammar, but the perceived connection to 'mīlia' (thousand) is not a given.

2510: etruscan and tuscany Oct 26, 2021

Often, etymologies for English words list that they are from Latin, and end there, but many Latin words had relatively ancient foreign origins of their own. A number of their words entered from the pre-Roman civilization of Etruscan who spoke a totally unrelated, non-Indo-European language, most obviously name of the region of Tuscany. This is from 'Tuscus', earlier 'Truscus', and even earlier 'Etruscus', but that doesn't exactly give the etymology. Rather, this is uncertain, but some surmise it is related to the Ancient Greek Τυρρηνός (Turrhēnós), from τύρρις (túrrhis) meaning 'tower', which itself is not of Indo-European origin. Alternatively, it has been noted among pre-Indo-European groups that they gave themselves names with -sk-, also seen in 'Basque' and 'Vascones', which is believed to mean 'water' and relate to seafaring peoples. Other explanations have traced to Celtic origins, or even to compare it to 'Troy', but these do not hold up as well. It has even been suggested that this was not the endonym, but rather 𐌓𐌀𐌔𐌍𐌀 (rasna) was what they called themselves, meaning 'the people'.

2509: No 'Loue' Lost: The Break-Vp of U&V Oct 25, 2021

The distinction of U and V as it is now was neither invented nor random, but even into the 16th century, there was not a clear distinction between V and U. Often, V was used in either case if it would fall at the beginning of a word, and in the middle or end of a word, it would be a U, regardless of sound. This discernment between U and V as a phonetic marker happened starting during the renaissance, since Germanic languages and even modern Romance languages have this sounds distinct, but the process was not immediate. This is also, in part, why many words have a so-called silent E at the end, as it helped with disambiguation when the sound was [v] as in 'love' but not 'low' (or 'lou', especially before W came on the scene).

2508: Ōs & Os: Two Very Different Destinies Oct 24, 2021

Latin differentiates between long and short vowels for distinguishing words, such as 'os' (bone) and 'ōs' (mouth). The other forms of 'ōs', including the genitive 'oris' is where 'oral' or 'orifice' get the R. Conversely, English has many derivatives like 'ossify', 'ossific', 'ossiferous', none of which have R in the root, because there was none present in any Latin form. 'Ōs' has far fewer derivatives outside of these other forms—except the use of 'os' as a medical term in English—including in Romance languages, relatively speaking. Consider too than 'mouth' is 'boca' in Spanish and Portuguese, ​'bocca' in Italian, and 'bouche' in French, all of which come from Latin 'bucca' (cheek) itself likely from a Celtic origin, likely related to 'pouch' of Germanic origin, and possibly related to 'puke'.

2507: Candace: Mistaken for a Biblical Name Oct 23, 2021

Candace is ostensibly a (New Testament) biblical name, but it was not actually a name. Referred to as a queen in the text, the word was written as Κανδάκη (Kandakē) in Greek, from Kdke in the Meroitic language of the Cushites, was a specific title for the sister of a king. This sort of terminology was commonly used around the region, especially around what is now Ethiopia, but later Greek and Roman sources misunderstood this and treated it as her personal name in Acts. This is how it came to be a name in English, despite it not technically being a biblical name, per se.

2506: Thai Months Oct 22, 2021

In modern Thai, months with 30 days end in '-ayon' and months with 31 end in '-akhom'; February (Kumphaphan) ends in '-phan'. Originally in Thai, the months were just numbered, but later these were Thai-modified Sanskrit named introduced by prince Devawongse Varoprakar based on the Zodiac signs, with both endings mentioned above meaning 'arrival'. This makes something like October 'tulakhom' from 'tulā' (balance) meaning 'the arrival of balance' from 'Libra', or April as 'Mesayan' from 'mesa' (ram) from Aries and so on. The different ending for February means 'bound', and the added day of a leap-year is called 'Athikasuratin' meaning 'additional'.