于焉 yúyān thereupon Origin Definitions Defs Strokes Stroke Words Sentences Sents 于 於 yú preposition in Indicates a location, scope, or time; equivalent to 在 zài焉 yān adjective [pronoun/prepositional] (literary) pronoun or prepositional phrase acting as a substitute for 之 zhī or 于 yú plus a pronoun, meaning him, her, it, them, or in, at, or from it