'uncolonnated' originates from English, formed from the negative prefix 'un-' and the adjective/verb 'colonnate' (related to 'colonnade'), where 'colonnate' meant 'having or arranged with columns'.

'colonnade' comes from French 'colonnade', ultimately from Italian 'colonna' and Latin 'columna' meaning 'column'; the negative formation 'un-' + base produced 'uncolonnated' in modern English usage as a descriptive adjective.

Initially terms like 'colonnade' and 'colonnate' referred to a row or arrangement of columns; over time the prefixed form 'uncolonnated' has come to mean simply 'lacking columns' in contrast to those terms.