'evenly-decorated' originates from English, formed from the adverb 'evenly' (from Old English 'efen' meaning 'level, equal' + the adverbial suffix '-ly') and the past-participle adjective 'decorated' (from Latin 'decorāre' meaning 'to adorn', from 'decor' meaning 'grace, beauty').

'evenly-decorated' developed in modern English as a transparent compound: Old English 'efen' became modern 'even' > 'evenly'; Latin 'decorāre' passed through Old French 'décorer' and Middle English variants to modern 'decorate' > 'decorated'. The hyphenated compound emerged in contemporary usage to describe uniform distribution of decoration.

Initially, it conveyed the straightforward sense of 'adorned in an equal manner', a meaning that has remained stable and is still current.