How to pronounce quadrant in English

"The fourth part; the quarter."

"The quarter of a circle or of the circumference of a circle an arc of 90� or one subtending a right angle at the center."

"One of the four parts into which a plane is divided by the coordinate axes. The upper right-hand part is the first quadrant; the upper left-hand part the second; the lower left-hand part the third; and the lower right-hand part the fourth quadrant."

"An instrument for measuring altitudes variously constructed and mounted for different specific uses in astronomy surveying gunnery etc. consisting commonly of a graduated arc of 90� with an index or vernier and either plain or telescopic sights and usually having a plumb line or spirit level for fixing the vertical or horizontal direction."