Yesterevening is a compound of yester- ('last, previous') + evening, from Old English ġeostran ('yesterday') + ǣfnung ('evening'). In current use it is a noun and adverb meaning "the evening of yesterday; last evening (archaic)". That sense is explained by the older material without requiring a speculative semantic step: the inherited or borrowed base supplies the field of meaning, while the English formation fixes its modern role. The surface form is compositional: its joined elements remain visible in the modern word. The historical chain includes Old English ġeostran and Old English ǣfnung. Related English forms include yesterday, yesteryear, and evening. The word's history is thus visible in its construction: the components remain interpretable even after the whole expression has settled into a conventional English meaning.