Meaning

noun a brittle silver-white metalloid element that is related to selenium and sulfur; it is used in alloys and as a semiconductor; occurs mainly as tellurides in ores of copper and nickel and silver and go

noun the syllable naming the seventh (subtonic) note of any musical scale in solmization

originSense 1: Altered from si in the 19th century to prevent having two notes of the musical scale starting with the same letter, to become te and later ti. Sense 2: The vowel of ti then changed to 'e' to signify a flattened note.

Etymology from Wiktionary, CC BY-SA 3.0