Entry 1 sense Webster, 1913 Acotyledon /(#; 277)/ · A·cot·y·le·don · IPA /ˈeɪ.kɔt.l̩.iːdˌn̩/ 01 n. A plant which has no cotyledons, as the dodder and all flowerless plants. 1. A plant which has no cotyledons, as the dodder and all flowerless plants.(Bot.)