lateral separation (air traffic control). The lateral spacing of aircraft at the same altitude by requiring operation on different routes or in different geographic locations.
lateral stability (aircraft stability). The stability of an airplane about its longitudinal axis, the axis passing through an airplane from nose to tail. If an airplane is disturbed from level flight so that one wing drops, lateral stability returns it to a level-flight attitude.
When a wing drops, the airplane begins to slip to that side, and the lift produced by the lowered wing increases. At the same time, the lift produced by the raised wing decreases. This uneven lift, caused by lateral stability, returns the airplane to level flight.

lateral vibration (helicopter operation). Vibration of a helicopter which causes the rotor to move back and forth in a lateral plane. Lateral vibration is often caused by an out-of-balance main rotor.
lathe (machine tool). A metalworking or woodworking power tool used to change the shape or size of cylindrically shaped objects. The material to be shaped is clamped horizontally in a chuck and is rotated. The unclamped end of the material is steadied by the lathe tail stock. Cutting tools are fed into the material from the side to remove unwanted material.
latitude. The angular measurement of distance on the surface of the earth, north and south of the equator. Latitude is measured in degrees, minutes, and seconds, and parallels of latitude cut the earth into imaginary parallel slices. The equator, which is zero degrees latitude, forms a belt around the center of the earth. The north pole is 90° north latitude, and the south pole is 90° south latitude.