'annulate' originates from Latin, specifically the word 'annulatus', where 'annulus' meant 'ring'.

'annulatus' passed into Late Latin and Middle English forms (via scientific and descriptive Latin usage) and eventually became the English adjective and verb 'annulate' and the adverb 'annulately'.

Initially it denoted 'provided with rings' (from 'ring'), and it has retained the core sense of 'ring-shaped' or 'marked by rings' in modern descriptive use.