A cusp in geometry is the point where two curves meet. It's a kind of transition. If you're on the cusp of manhood, you’re not quite grown up, but you’re definitely not a little boy anymore either.

The word comes from Latin cuspis, "point." You'll see lots of cusps in Gothic churches — a point where two arches meet, or where decorative curves meet to form a point. The little points that stick out on the surface of your teeth that are flat on top — the ones you use for grinding — are also called cusps. Those teeth right behind your canine teeth but before your molars have two cusps, and they're called bicuspids.

Definitions of cusp
  1. noun
    the limit beyond which something happens or changes
    synonyms: brink, verge
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    the brink of a dangerous or potentially disastrous situation
    type of:
    bound, boundary, limit
    the greatest possible degree of something
  2. noun
    point formed by two intersecting arcs (as from the intrados of a Gothic arch)
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    type of:
    sharp end
  3. noun
    a thin triangular flap of a heart valve
    synonyms: leaflet
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    type of:
    a movable piece of tissue partly connected to the body
  4. noun
    small elevation on the grinding surface of a tooth
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    type of:
    peak, point, tip
    a V shape
Word Family

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