1. not paired; occurring singly rather than in pairs
Usage: chiefly anatomical or biological
2. in anatomy, relating to or denoting a structure (such as a vein) that has no corresponding paired structure on the opposite side of the body
Usage: medical/anatomical term

Examples

• The azygous vein runs along the right side of the vertebral column without a paired counterpart on the left.
• In some organisms, certain organs are azygous, developing only on one side of the body.
• Medical students learn to identify azygous structures during anatomy class.
• The azygous system drains blood from the posterior thoracic wall.
• Unlike most veins, the azygous vein is unpaired and unique in its position.