A lemon is a type of fruit. The color of a lemon is yellow. It is a small fruit, and its shape is round or oval. A lemon has a thick skin. Inside, the fruit is light yellow and has juice. The juice is very sour. People use the juice for drinks and for food. They can add it to water with sugar to make a popular drink. Lemons also have small, white seeds inside. Lemons grow on a small tree. This tree needs a lot of sun to grow well. People do not eat the whole fruit.