leap year
Concise Oxford English Dictionary © 2008 Oxford University Press:
leap year
▶noun a year, occurring once every four years, which has 366 days including 29 February as an intercalary day.
– origin ME: prob. from the fact that feast days after February in such a year fell two days later than in the previous year, rather than one day later as in other years, and could be said to have ‘leaped’ a day.
'leap year' also found in these Oxford entries:
