In biology, antrum is a general term for a cavity or chamber which may have specific meaning in reference to certain organs or sites in the body.
The word Antrum can also be used as a surname in certain parts of the world.
In vertebrates, it may refer specifically to:
- antrum cardiacum, a dilation that occurs in the esophagus near the stomach (forestomach)
- antrum follicularum, the cavity in the epithelium that envelops the oocyte
- mastoid antrum, a cavity between the middle ear and temporal bone in the skull
- pyloric antrum, the initial portion of the pyloric part of the stomach. This is what usually is referred to in terms of "antrum" in stomach related topics.
- maxillary antrum or Antrum of Highmore, the maxillary sinus, a cavity in the maxilla and the largest of the paranasal sinuses
In invertebrates, it may mean specifically to:
- antrum of female lepidoptera genitalia