Less than the speed of sound in that medium.
If accelerating to the speed of sound, the subsonic.
subsonic
Subsonic means "slower than the speed of sound" so a subsonic bullet is any bullet that travels slower than the speed of sound.
Subsonic speed refers to speeds below the speed of sound in a medium. In water, the speed of sound is higher than in air, so typical speeds of objects moving through water are considered subsonic.
subsonic is moving below the speed of sound, supersonic is faster than speed of sound
Subsonic means any speed below the speed of sound. (Mach 1). So subsonic aircraft range from 0 - 661 knots at sea level. (Mach 1 is 661 knots at sea level.)
Subsonic
Speed has nothing to do with where you are. You can travel below the speed of sound pretty much anywhere.
Transonic speeds are when an object is moving near the speed of sound, experiencing a mix of subsonic and supersonic airflow. Subsonic speeds are when an object is moving at speeds below the speed of sound. At transonic speeds, airflow can become unpredictable, leading to effects like shock waves and buffeting.
One half the speed of sound. This is subsonic.
The main difference is the speed of the object in relation to the speed of sound. Subsonic refers to speeds slower than the speed of sound, while supersonic refers to speeds faster than the speed of sound. In the case of supersonic speeds, objects are traveling faster than the speed at which sound waves propagate in the medium.
The term subsonic can refer to speed that's lower than the speed of sound. In computer terms, this could mean an open source media server or refer to programming code.