The traditional abbreviation for a strikeout. A backwards K is often used to denote a called strikeout. Invented by Henry Chadwick by taking the "most prominent" letter of "struck" and reinforced by inference of "knockout" or "K.O." That connotation still exists, when the announcer says the pitcher "punched out" the batter, a play on words that also refers to "punching" a time clock and the punching motion that the home plate umpire usually makes on a called third strike.
Also singular, "keep off the board". Keep a team from scoring, and hence off the scoreboard. "Wainwright has kept runs off the board at a better rate than Lester." "After loading the bases with one down in the fourth, the Gators were kept off the board by Barham."
A pitcher needs to mix up his pitches and thereby "keep the hitter honest" by making it difficult for the hitter to anticipate the type, speed, and location of the next pitch. Sometimes this means throwing a brushback pitch to keep the batter from leaning over the plate to reach a pitch on the outer part of the plate. "Partially with Boston in mind, Wang focused this spring on expanding his repertoire to keep hitters honest and move them off the plate."
A breaking ball (usually a curveball) that breaks very sharply, so much so that it freezes the hitter. Also refers to a breaking ball that starts out directly at the batter—so that his or her knees buckle out of fear from the belief that the pitch will hit him or her—but which then drops in the strike zone.
Knocks: Hard hits or extra-base hits, not necessarily producing RBIs or referring to a specific type of hit. "Curtis had some solid knocks today".
Knocked around: A pitcher who gives up a lot of hits and gets removed from the game is said to have been knocked around or knocked out of the box or knocked out of the game. Example headline: "Toronto 7, Detroit 4: Phil Coke knocked around; Tigers' bats don't respond".
Knock down: an infielder who stops a line drive from getting through the infield "knocks it down", perhaps then picking up the ball and throwing the runner out.
Knock off: to knock off an opponent is to win the game. "Hawai'i knocks off Santa Clara."
A pitch thrown with no spin, traditionally thrown with the knuckles, but also with the fingertips. It tends to flutter and move suddenly and erratically on its way to the plate. Also refers to a batted ball that flutters "like a knuckleball". SYNONYMS: knuckler, flutterball, butterfly ball, floater, bug.