plainer / planar / planer [pleinɜr]
plainer – adj. & n. – adj. – comparative form of plain – flatter, more simple; n. – grumbler, lamenter
planar – adj. – 1. related to two-dimensional space; 2. Electronics – having electrodes or other components located in parallel positions but in the same plane
planer – n. – 1. a person, tool or machine that makes something smoother or level; 2. Printing – a leather-covered wooden block used to tap down pieces of type