'aplite' originates from German, specifically the word 'Aplit', ultimately from Greek 'ἁπλίτης' (haplítēs) meaning 'simple' or 'single', referring to its relatively simple, uniform, fine-grained composition.

'aplite' was adopted into scientific German as 'Aplit' in the 19th century and was later borrowed into English as 'aplite'; the Greek root 'ἁπλ- (hapl-)' meaning 'simple' is the ultimate source.

Initially the root conveyed the idea of 'simple' or 'single'; over time the term came to denote this specific type of fine‑grained, compositionally simple igneous rock.