Entry 1 sense Webster, 1913 Quintine · Quin·tine · IPA 01 n. The embryonic sac of an ovule, sometimes regarded as an innermost fifth integument. Cf. Quartine, and Tercine. 1. The embryonic sac of an ovule, sometimes regarded as an innermost fifth integument. Cf. Quartine, and Tercine.(Bot.) See: Quartine, Tercine