Stound comes from Old English 'stund', a fixed period of time, a moment, from Proto-Germanic '*stundō', a point of time; later also a sharp pang. The historical chain includes Old English stund and Proto-Germanic *stundō. The quoted older senses, "stund" and "*stundō", supply the semantic anchors for stound. The formation is best read as borrowed: the word stound carries its older form-history into a compact English lexical shape. In present English it is used as a noun, "an archaic word for a moment, sharp pang, or time of trial". Related English forms include stun. The result is a noun whose etymology preserves both the older form and the later English specialization.