Entry 1 sense Webster, 1913 Beryllium /bərĭl'ēəm/ · Be·ryl·li·um · IPA /bəˈɹɪl.i.əm/ 01 n. A metallic element found in the beryl. See Glucinum. 1. A metallic element found in the beryl. See Glucinum.(Chem.) See: Glucinum