An Inflection

(grammar) A change in the form of a word that reflects a change in grammatical function. Inflection - Wikipedia
A change in pitch or tone of voice.
(mathematics) A change in curvature from concave to convex or from convex to concave.
A turning away from a straight course.
(optometry) diffraction

Synonyms

flection, flexion

Hyponyms

(grammar): conjugation
(grammar): declension, declination