Definition of lemon noun from the Oxford Advanced American Dictionary

Oxford3000

lemon

noun
/ˈlɛmən/
 
 
1 [countable, uncountable] a yellow citrus fruit with a lot of sour juice. Slices of lemon and lemon juice are used in cooking and drinkslemon teaYou need a lot of lemons to make lemonade.Squeeze the juice of half a lemon over the fish.a lemon tree2 [uncountable] lemon juice or a drink made from lemon3 (also lemon yellow) [uncountable] a pale yellow color4 [countable] (informal) a thing, especially a car, that is useless because it does not work as it should synonym dud