The headword is a masculine noun in the nominative (and vocative) plural; see generally LSJ s.v. It occurs, among other instances, at Homer, Iliad 1.570 (web address 1). Here, however, the reference is to Olympian gods other than the Titans.
[1] A scholion to Homer, Iliad 5.898 (web address 2), where the headword appears in the genitive plural (*ou)raniw/nwn), likewise identifies the Titans, qua children of Ouranos; cf. tau 676, tau 677, and tau 680. The scholion is in fact misleading, as this passage too does not concern the Titans.