'ridged-billed' originates from Modern English, specifically the compound of 'ridged' and 'billed', where 'ridged' derives from 'ridge' (Old English 'hrycg') meaning 'back; raised line' and 'billed' derives from 'bill' (Old English 'bile'/'billa') meaning 'beak'.

'ridged-billed' was formed in Modern English by combining the past-participle adjective 'ridged' (from 'ridge') with 'billed' (from 'bill'), following a long English practice of compounding descriptive past-participial adjectives with nouns to form attributive compounds (e.g., 'broad-winged', 'long-legged').

Initially, the individual elements meant 'ridge' (a raised line) and 'bill' (beak); when compounded as 'ridged-billed' the phrase came to mean specifically 'having a beak with a ridge', a narrow zoological/ornithological descriptive usage that has remained consistent.