Relating to or resembling a column; having the form or character of a column.
From Latin columna 'column' + -ar (adjective suffix). This is an alternative form to 'columnar,' both deriving from the Latin root and used somewhat interchangeably in technical contexts.
Colunar is the rarer, more technical variant of columnar—scientists might use it to sound more Latin and precise, but in modern English, columnar has almost completely replaced it. It's a word slowly disappearing as language naturally selects simpler forms.
Complete word intelligence in one call. Free tier — 50 lookups/day.