Entry 1 sense Webster, 1913 Signor /sēn'-yôr/ · Si·gnor · IPA /ˈsiːnjɔr/ 01 n. Sir; Mr.; -- a title of address or respect among the Italians. Before a noun the form is Signor. 1. Sir; Mr.; -- a title of address or respect among the Italians. Before a noun the form is Signor.