Definition of mammillary in US English:


(also mamillary)


  • 1Shaped like or resembling a breast or nipple.

    • ‘The grounds in the neighborhood are covered with those common mammillary elevations known as ‘Indian corn-hills.’’
    1. 1.1 (of minerals) having several smoothly rounded convex surfaces.
      • ‘Malachite is typically massive, forming thick, compact crusts with mammillary surfaces.’
      • ‘Shell units are tightly packed but separated in the mammillary layer.’
      • ‘Pale-to-medium blue mammillary rosasite aggregates occur with malachite in oxidized rock fallen from the north face of the open pit near the decline access drift.’
    2. 1.2Anatomy Denoting two rounded bodies in the floor of the hypothalamus in the brain.
      • ‘This could, in turn, explain why mammillary body damage seems to preferentially affect memory on spatial tasks.’
      • ‘Especially in these cases, MRI findings with high signal intensity in the thalamus and mammillary bodies can be especially important.’
      • ‘It was bluntly perforated in front of the mamillary bodies with the aid of a catheter.’
      • ‘The hippocampus has output to the mamillary bodies and onto the anterior nucleus of the thalamus.’
      • ‘The hippocampus, fornix, and mamillary bodies have an integral role in memory and learning.’


Early 17th century: from modern Latin mamillaris, from mamilla (see mammilla). The spelling variant of -mm- was due to association with mammary.