This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Of, relating to, or situated in a plane.

adj. Flat: a planar surface.

adj. Having a two-dimensional characteristic.

adj. Of or pertaining to a plane.

adj. Flat, two-dimensional.

adj. Able to be embedded in the plane with no edges intersecting.

Lying in a plane; planary; flat.

Of or pertaining to a plane.

n. See anastigmat.

adj. involving two dimensions

"Contrary to earlier claims, we find that the amount of power concentrated in planar modes for $\ell = 2,3$ is not inconsistent with isotropy and Gaussianity."

tabular    planate    flat    flattened    placoid    coplanar    platelike   

planar dyadic    planar lens   

plane   

nonplanar   

Gaynor    Mainer    Rainer    campaigner    complainer    container    craner    drainer    entertainer    gainer   

bimodal    point-set    acyclic    two-dimensional    straight-line    orthogonal    topological    3-dimensional    three-dimensional    radial