A vertical (or nearly vertical) rock face.
"The old manuscript contains an archaic note where the term cliff is used as an obsolete form of clef to indicate the starting pitch of a musical line."
Obsolete form of clef.
In plain English: A cliff is a steep rock face that goes straight down to the ground below.
"We walked carefully along the edge of the steep cliff to avoid falling into the water below."
Usage: Use this term to describe any steep, near-vertical drop of earth or rock rather than just those found at coastlines. Avoid confusing it with similar words like precipice when a less dramatic but still dangerous slope is intended.
A diminutive of the male given name Clifford or Clifton.
"The new resident, Cliff, often joked about his nickname being a diminutive of the original surname Clifford."
The word cliff comes directly from the Old English term for a steep rock face or precipice. It traveled into modern usage without changing its original meaning of describing high, vertical rocks along coastlines.