billable

The word 'billable' is a modern legal and commercial formation, directly combining the English word 'bill' with the productive suffix '-able'. Its core logic is transparent: if something (like time or a service) is 'billable', it is capable of being included on a bill or invoice to be charged to a client. The root 'bill' itself has a long journey, originating from Medieval Latin bulla meaning a sealed document or papal edict, which evolved in Anglo-Norman to mean a written list or formal petition, eventually narrowing in English to its specific financial sense. The suffix '-able', of Latin origin via French, is one of the most common and active in English for creating adjectives that express potential or suitability, making 'billable' a clear and logical compound for professional contexts.

Structure: bill (charge/invoice) + able (capable of) - bill: From Middle English bille, from Anglo-Norman bille, from Medieval Latin billa/bulla (a sealed document, list). Functions as the core noun/verb root meaning a formal list of charges or the act of charging. - able: From Old French -able, from Latin -abilis (capable of, fit for). Functions as a suffix forming adjectives meaning "capable of, fit for, or worthy of" the action of the root verb.