A lemon is a common fruit. The color of a lemon is yellow. Its shape is oval. The skin of a lemon is thick and not smooth. Inside, the fruit is wet with juice. The taste of the juice is very sour. It is not sweet. Lemons grow on small trees in warm places. People use lemons in the kitchen. They put the juice in water to make a drink. They also put it on food, like fish or salad. Lemon juice has a lot of vitamin C. This vitamin is good for your health.