the GNU version of the Collaborative International Dictionary of English
n. A small, overhanging structure for lookout or defense, usually projecting at an angle of a building or near an entrance gateway.
The Century Dictionary and Cyclopedia
n. In architecture, a small overhanging turret, pierced with loopholes or embrasures, or with both, and projecting generally from an angle at the top of a tower, or from the parapet of a building or medieval fortification-wall.
Word Usage
"The heavy yet hasty step of the men-at-arms traversed the battlements, or resounded on the narrow and winding passages and stairs which led to the various bartizans [Footnote: A bartizan is a sort of small overhanging balcony, built for defense or for lookout.] and points of defense."