Military term, a squad is usually devided into fireteams (usually with 4 men each) and a Squad leader to command them.
Here is an example of a 11-man squad (in this example, Fireteam Green is a sharpshooter team):
-Spotter and Green lead
Please note that certain terms etc. may differ between units. Eg, instead of Red, Blue etc. the fireteams may be designated Alpha, Bravo etc.
Squad lead-"Red, move two-by-two up to that berm, when you signal your clear, Fireteam Blue will move up on the left"
Red lead-"Fuckin' A sir, Fireteam, prepare to move up, Riflemen one and three, you move first, two by two, Rifleman two, on me"