Entry 1 sense Webster, 1913 Soldering · Sol·der·ing · IPA /ˈsɑdəɹɪŋ/ 01 a. & n. a. & n. from Solder, v. t. 1. a. & n. from Solder, v. t. See: Solder Phrases & compounds Soldering iron — an instrument for soldering, consisting of a bit or bolt of copper having a pointed or wedge-shaped end, and furnished with a handle.