The onions mentioned in Numbers 11:5 are certainly Allium cepa, the Egyptian onion. This onion has a compact bulb covered with a coat and formed of layers. These layers consist of broad, fleshy bases of leaves that closely overlap each other. The leaves are slender and hollow. The entire plant has a strong, distinctive taste and smell.
Onion
From Tyndale Bible Dictionary, adapted by Mission Mutual. CC BY-SA 4.0.