Sauro (þ) (1), usually in longer form Sauron (þ), masc. name "the Abhorred", name of a Maia, the second Dark Lord (said to be the name by which he was "afterwards called", MR:147; according to PE17:183, his original name was Mairon, q.v.). Earlier Thauron (SA:thaur, THUS), archaic *Θaurond- (Letters:380, where the initial Greek letter represents th). The stem of Sauron* would then be Saurond-. Another form of the name is Súro**.
Quenya
Sauro
carpenter, wright, builder
Sauro
the abhorred
saura
foul, evil-smelling, putrid
saura (þ) adj. "foul, evil-smelling, putrid" (THUS), "foul, vile" (PE17:183). This adjective underlies the name Sauro, Sauron (q.v.) Alternatively explained to mean "cruel" (PE17:184); a deleted gloss defined the word as "bad, unhealthy, ill, wretched" (PE17:172). Tolkien did not consistently hold that the initial s represents older þ; sometimes he derived saura (and so implicitly Sauron) from stems with original s-.
Thauron
thauron
†Thauron (þauron) masc. name, earlier form of Sauron, before the change th > s (SA:thaur, cf. Letters:380, which suggests a stem _θ_aurond-; the initial Greek letter represents th). See Sauro, Sauron.
samno
carpenter, wright, builder
samno (þ) noun "carpenter, wright, builder" (STAB)
[sauro] (2) (þ) noun "carpenter, wright, builder", changed by Tolkien to samno (VT46:15)