Added 10 October 2026 phellem noun Categories: NatureObscure Words noun ! Definition from WordNet 3.1, Princeton University. More about phellem at Wordnik → Where our words come from → (botany) outer tissue of bark; a protective layer of dead cells. Related Words: corkphellogenphellodermphelodermepiphloemperidermendophloeumepiphloeumepiphlœumphloëmphlœmphelloplastic Back to today's word