What kind of steam does an onion have, a tuber, bulb, rhizome, or corm?

Question

What kind of steam does an onion have, a tuber, bulb, rhizome, or corm?

Answer 1

I think you mean root and not stem and it would be a bulb..

Answer 2

the answer IS "a bulb" but a bulb is not a root!! A bulb is actually a collection of swollen leaf-bases that makes a storage organ that can remain dormant until the Spring. The stem part of an onion is the very base that everything else is attached to.