## As a adjective **planar**

is of or pertaining to a plane.

## As a noun **ring** is

a circumscribing object, (roughly) circular and hollow, looking like an annual ring, earring, finger ring etc or

**ring** can be the resonant sound of a bell, or a sound resembling it or

**ring** can be (algebra) an algebraic structure which consists of a set with two binary operations, an additive operation and a multiplicative operation, such that the set is an abelian group under the additive operation, a monoid under the multiplicative operation, and such that the multiplicative operation is distributive with respect to the additive operation.

## As a verb **ring** is

to surround or enclose or

**ring** can be of a bell, to produce sound;.