Meaning

noun ornament consisting of a circular rounded protuberance (as on a vault or shield or belt)

noun heavy pin having a head at one end and the other end being hammered flat after being passed through holes in the pieces that are fastened together

verb direct one's attention on something

originFrom Old French rivet (13th century), from the verb Old French river (“to fetter [a person]”) (12th century), from Old French rive (“rim, edge”) (ca. 1100), which is ultimately from Latin ripa (“riverbank”). Compare river, rival, riparian. The sense "kind of footman's armour" is apparently a back-formation from almain rivet, which is apparently derived from the English noun; see that entry for…

Etymology from Wiktionary, CC BY-SA 3.0