Wiktionary
azimuth thruster
n. 1 a propulsive thruster located in an azimuth adjustable mounting 2 (context nautical English) an engine and ship's propeller in an underslung pod that is azimuth adjustable, to replace a fixed-azimuth propeller and rudder configuration
Wikipedia
Azimuth thruster
An azimuth thruster is a configuration of marine propellers placed in pods that can be rotated to any horizontal angle ( azimuth), making a rudder unnecessary. These give ships better maneuverability than a fixed propeller and rudder system.