1686: piglet and pig Jul 27, 2019
The word 'piglet', for a concept so old, is relatively new, the first known use coming from the mid-19th century. Before this there were some earlier words like 'hogling', used in Middle English, or even 'porket', coming from French. What all of these examples, and even others not included here tend to have is a diminutive suffix on another word meaning 'adult pig', but even before 'hogling', there was no need for this. The Old English word for 'piglet' was 'picg' (same as 'pig') but this was not any less precise, because an adult would only be called a 'swine' (sƿín).
Watch more on etymology here: https://youtu.be/AviuxNIvdPM