Planar

How to spell planar

6 letters · 2 syllables

How to pronounce planar

Say the part in capitals loudest.

What does planar mean?

1. adjectiveLying in or relating to a single flat plane; two-dimensional or flat.

Planar in a sentence

• The engineers tested whether the polished panel was perfectly planar before installation.

• A planar graph shows the molecule's atoms arranged on one flat surface.

Where does planar come from?

Language of origin: Latin

Planar comes from the Latin planum, meaning 'a flat surface' or 'level ground', which is the neuter form of planus, 'flat' or 'even'. The same planus root lies behind a whole family of English words, including 'plain' (an open, flat stretch of land), 'plane' (a flat geometric surface), and even 'explain', which originally meant to lay something out flat so it could be understood. The modern adjective planar was coined relatively late, in the nineteenth century, as a technical term in geometry and physics to describe anything lying within a single flat plane. It was built by attaching the Latin-derived suffix -ar, meaning 'relating to', directly onto that plan- stem, on the same pattern as words like 'lunar' and 'polar'. Remembering that it shares its flat-surface ancestry with 'plane' helps fix the single 'a' before the 'r' rather than any softer ending.

How the word is built

• plan- (from Latin planum: flat surface)
• -ar (adjective suffix meaning 'relating to')