"Pressures" and "hurries" are terms used to describe pass rushes which successfully alter a quarterback's performance on a play — forcing them to throw before they find their best target or scramble out of the pocket to elude being tackled — that fall short of completed sacks.
A related form of defensive rush is to disrupt or sack a kicker attempting to kick a field goal, extra point, or punt the ball.
In both college and professional football, getting a strong pass rush is an important skill, as even an average quarterback can be productive if he has enough time to find an open receiver, even against a good secondary.
To increase pressure, teams will sometimes use a pass-rushing specialist, who is usually a quick, strong defensive end or outside linebacker tasked with aggressively rushing the quarterback in obvious passing situations.
Other formidable historic pass rushers include Lawrence Taylor (#14, 132+1⁄2), the highest ranking pure linebacker, and Jim Katcavage, NFL leader in 1962 and 1963, a defensive tackle.