Irish county, from Irish Tir Eoghain "Eoghan's Land," from Eoghan "Owen," ancestor of the O'Neills, who owned land here. Tir also forms the final syllable in Leinster, Munster, Ulster.

white, crystalline amino acid, 1857, coined 1846 by German chemist Justus von Liebig (1803-1873), who had first obtained it a year before from the products of a fusion of old cheese and potash, from Greek tyros "cheese" (from PIE *tu-ro-, from root *teue- "to swell") on the notion of "a swelling, coagulating") + chemical suffix -ine (2).

1650s, "pertaining to the Etruscans," from Latin Tyrrheni, from Greek Tyrrenoi "Tyrrhenians," from tyrsis "tower, walled city" (cognate with Latin turris "tower"). Earlier Tyrrhene (late 14c.).