The length of the pulse is referred to as:

The length of the pulse in ultrasound terminology is referred to as spatial pulse length. Spatial pulse length measures the physical length of one pulse of ultrasound and encompasses the entire distance covered by that pulse in the medium. It is determined by both the number of cycles in the pulse and the wavelength of those cycles.

Spatial pulse length is critical in determining axial resolution, which is the ability to distinguish between two closely spaced structures along the direction of the ultrasound beam. A shorter spatial pulse length allows for better resolution, enabling finer detail to be picked up in the imaging process.

In contrast, other terms like pulse duration refer to the time it takes for one pulse to occur, while wavelength pertains to the distance between two consecutive peaks of a wave. Pulse repetition period, on the other hand, signifies the total time it takes for one pulse to be sent and another to follow, which is not related to the physical length of the pulse itself. Therefore, spatial pulse length accurately describes the concept of the length of the pulse in ultrasound.