Illustration of cusp
- 1 cusp d
a
: a point of transition (as from one historical period to the next) : turning point
b
: either horn of a crescent moon
c
: a fixed point on a mathematical curve at which a point tracing the curve would exactly reverse its direction of motion
d
: an ornamental pointed projection formed by or arising from the intersection of two arcs or foils (see foil entry 2 sense 4)
e(1)
: a point on the grinding surface of a tooth
(2)
: a fold or flap of a cardiac valve
Cite this Entry
“Cusp.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cusp. Accessed 4 Sep. 2026.
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