the.com/squirt gun

means A toy that shoots a thin jet of water from a reservoir squeezed or pumped by hand.

from A straightforward compound: 'squirt' (to eject liquid in a thin, forceful stream, echoing the sound itself — attested since the 16th century) plus 'gun,' borrowed for any device that shoots something. The term 'squirt gun' emerged as a plain American descriptor once simple rubber-bulb and plunger water toys became common, with 'water pistol' arising later as a fancier, more gun-shaped rival name for the same mischief-making device.