Loop
the curved path of the ball bowled by a spinner. Loosener
a poor delivery bowled at the start of a bowlers spell. Lost ball
A ball which cannot be retrieved, due to being lost or otherwise out of reach (e.g. hit into a river or over a fence). The umpire calls dead ball to stop play, and the batsman is credited with any runs completed (generally a boundary) or in progress at the time dead ball is called. A replacement ball is selected, preferably a used one in similar condition to the lost ball. Lower order (colloquially the tail) 
the batsmen who bat at between roughly number 8 and 11 in the batting order and who may have some skill at batting, but are generally either specialist bowlers or wicket-keepers with limited batting ability. Such batsmen are known as lower order batsmen or tail-enders. Lunch
the first of the two intervals taken during a full days play, which usually occurs at lunchtime at about 12:30 pm (local time). M
Maiden over
an over in which no runs are scored off the bat, and no wides or no-balls are bowled. Considered a good performance for a bowler, maiden overs are tracked as part of a bowling analysis. Makers name
the full face of the bat, where the manufacturers logo is normally located. Used particularly when referring to a batsmans technique when playing a straight drive, so that the opposing bowler has full view of the batsmans bat label (e.g., "Sachin Tendulkar played a beautiful on-drive for four, giving it plenty of makers name...").
Jaffa (also corker) 
an exceptionally well bowled, practically unplayable delivery, usually but not always from a fast bowler. Jayadevans system
an unsuccessful proposal for a rain rule, as an alternative to the Duckworth-Lewis system. Has never been used in professional cricket. Jockstrap (also jock strap)
underwear for male cricketers, designed to securely hold a cricket box in place when batting or wicket keeping. Just not cricket
see its (just) not cricket

K
Keeper
see wicket-keeper

Keep wicket
1. For a wicketkeeper to field. 2. "Keep wickets in hand", which is when a batting team tries to have relatively few of its batters get out. Usually done so that more run-scoring risks can be taken near the end of their innings in a limited-overs match, since they will have many batters left and only a few balls left. King pair
see Golden pair. Knock
a batsmans innings. A batsman who makes a high score in an innings can be said to have had a "good knock". Knuckle ball
A type of delivery where the fast bowler holds the ball on the knuckles of their index and middle finger. A type of slower ball. Kolpak
an overseas player who plays in English domestic cricket under the Kolpak ruling. Kwik cricket
(or quick cricket) An informal version of cricket with sped-up rules, specifically designed to introduce children to the sport. L
Lappa
The Indian version of the hoik. Comes from the English lap, an old term for a stroke somewhere between a pull and a sweep.