leap Idioms & Phrases
leap day

noun the name of the day that is added during a leap year
February 29; bissextile day.
WordNet
leap out

verb be highly noticeable
jump; jump out; stick out; stand out.

verb jump out from a hiding place and surprise (someone)
sally out; rush out; burst forth.
 The attackers leapt out from the bushes
WordNet
leap second

noun a second (as measured by an atomic clock) added to or subtracted from Greenwich Mean Time in order to compensate for slowing in the Earth's rotation
WordNet
leap year

noun in the Gregorian calendar: any year divisible by 4 except centenary years divisible by 400
intercalary year; bissextile year; 366 days.
WordNet
Leap" year`
Definitions
. Bissextile; a year containing 366 days; every fourth year which leaps over a day more than a common year, giving to February twentynine days. See Bissextile .✍ Every year whose number is divisible by four without a remainder is a leap year, excepting the full centuries, which, to be leap years, must be divisible by 400 without a remainder. If not so divisible they are common years. 1900, therefore, is not a leap year.
Webster 1913
quantum leap

noun a sudden large increase or advance
quantum jump.
 this may not insure success but it will represent a quantum leap from last summer