cusp
UK: kʌsp | US: kʌsp
n. a pointed end where two curves meet (e.g., the tip of a crescent moon)
n. a transitional point between two states or phases (e.g., "on the cusp of adulthood")
n. (dentistry) a raised point on the chewing surface of a tooth
The word "cusp" originates from the Latin cuspis, meaning "point" or "spear." It entered English in the late 16th century, retaining its core idea of a sharp or tapered end. Over time, it expanded metaphorically to describe transitional moments (e.g., "on the cusp of change"), likening abstract transitions to physical points of intersection.
The crescent moon’s cusp gleamed faintly in the night sky.
She stood on the cusp of a major career breakthrough.
The dentist noted an unusual wear pattern on the cusps of his molars.
The debate placed the candidate on the cusp of public recognition.
The rocket’s trajectory reached the cusp of Earth’s atmosphere before descending.