a axis: The angle that specifies the rotation of a machine tool about the x axis.
A block: A hollow concrete masonry block with one end closed and the other open and with a web between, so that when the block is laid in a wall two cells are produced.
A frame: A dwelling whose main frames are in the shape of the letter A.Two poles supported in an upright position by braces or guys and used for lifting equipment. Also known as double mast.
A size: One of a series of sizes to which trimmed paper and board are manufactured, for size AOf a sheet of paper, the dimensions 8.5 inches by 11 inches (216 millimeters by 279 millimeters).
A-mast: An A-shaped arrangement of upright poles for supporting a mechanism designed to lift heavy loads.
abandon: To stop drilling and remove the drill rig from the site of a borehole before the intended depth or target is reached.
abat-jour: A device that is used to deflect daylight downward as it streams through a window.
abat-vent: A series of sloping boards or metal strips, or some similar contrivance, to break the force of wind without being an obstruction to the passage of air or sound, as in a louver or chimney cowl.
abattoir: A building in which cattle or other animals are slaughtered.
ablatograph: An instrument that records ablation by measuring the distance a snow or ice surface falls during the observation period.
abnormal reading: NULL
abnormal time: During a time study, an elapsed time for any element which is excessively longer or shorter than the median of the elapsed times. Also known as abnormal reading.
abort branch: A branching instruction in the program controlling a robot that causes a test to be performed on whether the tool-center point is properly positioned, and to reposition it if it drifts out of the acceptable range.
Abrams' law: In concrete materials, for a mixture of workable consistency the strength of concrete is determined by the ratio of water to cement.