'astomatal' originates from Neo‑Latin/Modern Latin, specifically formed from the privative prefix 'a-' plus 'stomatal' (from Greek 'stoma'), where 'a-' meant 'without' and 'stoma' meant 'mouth' or 'pore'.

'astomatal' was formed in scientific Neo‑Latin as a negative compound of 'stomatalis' (relating to 'stoma') and was adopted into English scientific usage as 'astomatal' to describe plant parts lacking stomata.

Initially it meant 'without a stoma (pore)', and over time the meaning has remained essentially the same, used specifically in botanical contexts to indicate absence of stomata.