Is bell a noun

Yes, the Word 'bell' is both a noun (bell, bells) and a verb (bell, bells, belling, belled).

The noun 'bell' is a Word for a hollow metal device that makes a ringing sound when struck; an electric device that makes a ringing sound; a ringing sound used as a signal; a Word for a thing.

The verb 'bell' is to take the shape of a bell, to flare; to equip with a bell or bells.