Turret
Also: Tactical Turret · Capped Turret
An adjustment knob on the scope, typically one for elevation (top) and one for windage (right). Used to move the reticle relative to the bore.
Exposed (tactical) turrets are designed to be dialed in the field. Each click moves the reticle a known angular value, 0.1 mil or 1/4 MOA typically. Capped turrets are protected against accidental rotation; the shooter zeros and forgets.
Premium turrets have crisp tactile detents and a numbered scale. Cheap ones slip, lie about their values, and accumulate error across full rotations. That’s the reason “scope tracks honestly” is a top criterion in any precision-rifle scope buying decision.