Synonym of watchtower

In a high building, a stairway protected by several inches of concrete and entered through a kind of "air lock" that prevents the poluted smoke to enter inside it.

plural of lookout tower

plural of radio tower

(aviation) An airport building from which the air traffic control unit monitors and directs the movement of aircraft on and around the airport.

A bascule bridge in London crossing the River Thames, built in the late 19th century

plural of Martello tower

(physics, engineering) A tower, containing a long evacuated tube, within which objects can be dropped experimentally. / An amusement ride in which riders experience free fall.

(mathematics) A chain of exponentiations, or raising to powers, of the form a^(aa...); tetration.

plural of power tower