Entry 2 senses Webster, 1913 Marginally · Mar·gin·al·ly · IPA /ˈmɑɹd͡ʒɪnəli/ 01 adv. In the margin of a book. 1. In the margin of a book. 2. In a marginal{3} manner; barely sufficiently; almost not; as, marginally useful. See: marginal