The phrase "volume toggle" refers to a button or control that adjusts the loudness of sound, like turning up or down the volume on a device such as a phone, computer, or speaker. Full definition
There are five familiar controls — send, home, Start, back and end — beneath the 4.3 - inch, 480 x 800 capacitive touchscreen, and only a nearly flush volume toggle on the left spine. (digitaltrends.com)
The top edge has the power button and volume toggle button. (pocketnow.com)
On the base is the microUSB back, up top is the 3.5 mm headphone jack and the power button, on the right a solid, nearly flush volume toggle often difficult to control by feel, and the camera shutter button. (digitaltrends.com)