'capitalizable' originates from Modern English, specifically the verb 'capitalize' plus the adjectival suffix '-able', where '-able' meant 'capable of being'.

'capitalize' came into English from French 'capitaliser' and Late Latin/Medieval Latin forms such as 'capitalizare', which in turn derive from Latin 'capitalis' (related to 'caput', meaning 'head'). Over time the verb formed the adjective with '-able' to produce 'capitalizable'.

Initially related to the notion of 'head' or 'principal' (from Latin 'caput'), the sense shifted to 'making something principal or recording as capital' and to the orthographic sense 'make a letter uppercase'; 'capitalizable' now means 'able to be made capital' in both financial and typographic senses.