Entry 2 senses · 2 variants Webster, 1913 Bifocal /bīf'-ōk-əl/ · Bi·fo·cal · IPA /bˈaɪfoʊkəl/ a. n. 01 a. Having two foci, as some spectacle lenses. 1. Having two foci, as some spectacle lenses. 02 n. a bifocal lens. 1. a bifocal lens.