A vent opening is a type of opening in a wall or ceiling that allows air to flow through. The two crossword solutions for the term 'vent opening' are PRE (3 letters) and LOUVER (6 letters). PRE is an abbreviation for 'prefabricated, ' which means that the vent opening is made from pre-made parts. LOUVER is a type of vent opening that has angled slats, allowing air to pass through while still providing some privacy.