louver in Portuguese

A type of turret on the roof of certain medieval buildings designed to allow ventilation or the admission of light. [from 14th c.]

(chiefly, _, in plural) A series of sloping overlapping slats or boards which admit air and light but exclude rain etc. [from 16th c.]

(chiefly, _, in plural) A series of sloping overlapping slats or boards which admit air and light but exclude rain etc. [from 16th c.]

Any of a system of slits, as in the hood of an automobile, for ventilation.