cheek

The cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. The area between the inside of the cheek and the teeth and gums is called the vestibule or buccal pouch or buccal cavity and forms part of the mouth. "Buccal", from Latin " buccae", means relating to the cheek. In other animals the cheeks may also be referred to as jowls. Some animals such as squirrels and hamsters use the buccal pouch to carry food or other items.

Cheeks are fleshy in humans, the skin being suspended by the chin and the jaws, and forming the lateral wall of the human mouth, visibly touching the cheekbone below the eye. The inside of the cheek is lined with a mucous membrane [黏膜].

During mastication (chewing), the cheeks and tongue between them serve to keep the food between the teeth.

The cheek is the most common location from which a DNA sample can be taken (during a cheek swab).

Sometimes people refer to the buttocks as the "cheeks", because of their semi-round appearance. 汉语有“脸蛋”和“屁股蛋”的说法。

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If a part of someone's body, especially their face, is puffy, it has a round, swollen appearance, e.g. "a girl with puffy cheeks".

• You say that someone has a cheek when you are annoyed or shocked at something unreasonable that they have done. 
• If you say something with your tongue in your cheek, you say it as a joke, not seriously.
• If you turn the other cheek when someone harms or insults you, you do not harm or insult them in return.

cheek by/to cheek/jowl - physically close enough to touch cheeks; close together

• A: "What makes you say that Eddie and Tara got back together?" B: "Well, I just saw them dancing cheek to cheek in the ballroom, for starters."
• I hate having to stand cheek to cheek with strangers on the subway during rush hour.