Isolated mathematical point

Wiktionary Word definitions in Wiktionary
n. (context geometry English) An isolated point not upon a curve, but whose coordinates satisfy the equation of the curve so that it is considered as belonging to the curve.

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Acnode \Ac"node\, n. [L. acus needle + E. node.] (Geom.) An isolated point not upon a curve, but whose co["o]rdinates satisfy the equation of the curve so that it is considered as belonging to the curve.

Wikipedia Word definitions in Wikipedia
An acnode is an isolated point not on a curve , but whose coordinates satisfy the equation of the curve. The term " isolated point or hermit point " is an equivalent term. Acnodes are commonly found in the study of algebraic curves over fields which are ...