Trail braking
Trail braking is easing off the brakes gradually as you turn into a corner, blending braking and cornering grip instead of releasing all at once.
Also called: trailing the brakes, brake trailing
In a novice's corner, braking ends abruptly before turn-in, and the car coasts into the turn. Trail braking keeps some brake pressure on past turn-in and releases it smoothly as steering is added. The car keeps weight on the front tires, which helps it turn, and the tires use their grip continuously rather than leaving a gap.
From the seat, it feels like the car rotating willingly toward the apex while you gently roll off the brake. Your foot comes off the pedal progressively, often reaching zero near the apex, just as cornering load peaks.
The mistakes come at both extremes. Releasing too abruptly unloads the front and causes understeer. Holding too much brake too deep can overload the rear and cause oversteer. Learn it with an instructor, at modest speed, building up release smoothness before pushing the depth.
Trail braking lets you brake later and turn better, often one of the biggest skills separating intermediate and advanced drivers.
Each tire can only make so much force. Brake hard and there's little left for turning. Blend one into the other (trail braking) and you stay near the edge of the circle the whole time.