'arciform' originates from Modern Latin 'arciformis', ultimately from Latin 'arcus' meaning 'bow' combined with the English combining form '-form' meaning 'shape'.

'arciform' derived from Late/Modern Latin 'arciformis' (formed from Latin 'arcus' + '-formis') and entered English usage as a learned adjective meaning 'bow-shaped'.

Initially it carried the straightforward sense 'bow-shaped' from the Latin root 'arcus'; this basic sense has been retained in modern usage as 'shaped like an arc'.