The lemon (Citrus × limon) is a species of small evergreen tree native to Asia.
The tree's ellipsoidal yellow fruit is used for culinary and non-culinary purposes throughout the world, primarily for itsjuice, which has both culinary and cleaning uses.[1] The pulp and rind (zest) are also used in cooking and baking. The juice of the lemon is about 5% to 6% citric acid, which gives a sour taste. The distinctive sour taste of lemon juice makes it a key ingredient in drinks and foods such as lemonade and lemon meringue pie.
可以参照维基百科解释https://en.wikipedia.org/wiki/Lemon