'specialize' originates from French, specifically the verb 'spécialiser', where 'special-' meant 'particular' and the verbal suffix '-iser' was used to form verbs.

'specialize' developed from Middle English adjective 'special' (from Old French 'especial' / 'special'), which in turn came from Latin 'specialis' (related to 'species'). The verb form in English was modeled on French 'spécialiser' and formed as 'specialize' in modern English.

Initially related to making or marking something 'particular' or 'special'; over time the verb came to mean 'to concentrate on or become an expert in a particular area'.