'baetylus' originates from Ancient Greek, specifically the word 'βαίτυλος' ('baitylos'), where the term referred to a sacred or divinely endowed stone.

'baetylus' passed into Latin as 'baetylus' from Greek 'baitylos' and was later borrowed into English with the same basic form and meaning.

Initially, it meant 'a sacred (often meteor) stone' in Greek, and over time it retained this specialised meaning in English as a term for stones venerated as divine or endowed with power.