Definition of mammillary
1
: of, relating to, or affecting a nipple, breast, or duct of the mammary gland
- mammillary tissue
- a mammillary fistula
2 a
: resembling a breast or nipple especially in having a rounded shape
- the mammillary process of a lumbar vertebra
b
: studded with breast-shaped protuberances
- mammillary forms of agate
3
: of or relating to a mammillary body
- the mammillary region of the brain
- mammillary nuclei
