The word 'occasionally-used' is a compound formed from 'occasionally' (from 'occasion') and 'used' (past participle of 'use'). 'Occasionally' comes from the Latin 'occasio' meaning 'opportunity' and 'used' from Latin 'uti' meaning 'to use'.

'Occasionally-used' is a modern English compound, combining the adverb 'occasionally' and the adjective 'used' to describe something that is not used often.

Initially, the parts meant 'used from time to time', and this meaning has remained consistent in the compound form.