Inflection

[in-flek-shuh n] /ɪnˈflɛk ʃən/

noun
1.
modulation of the voice; change in pitch or tone of voice.
2.
Also, flection. Grammar.

3.
a bend or angle.
4.
Mathematics. a change of curvature from convex to concave or vice versa.
/ɪnˈflɛkʃən/
noun
1.
modulation of the voice
2.
(grammar) a change in the form of a word, usually modification or affixation, signalling change in such grammatical functions as tense, voice, mood, person, gender, number, or case
3.
an angle or bend
4.
the act of inflecting or the state of being inflected
5.
(maths) a change in curvature from concave to convex or vice versa See also point of inflection
n.

early 15c., from Middle French inflexion and directly from Latin inflexionem (nominative inflexio) “a bending, inflection, modification,” noun of action from past participle stem of inflectere (see inflect). For spelling, see connection. Grammatical sense is from 1660s.

inflection in·flec·tion (ĭn-flěk’shən)
n.
An inward bending.

A change in the form of a word to reflect different grammatical functions of the word in a sentence. English has lost most of its inflections. Those that remain are chiefly possessive (‘s), as in “the boy’s hat”; plural (-s), as in “the three girls”; and past tense (-d or -ed), as in cared. Other inflections are found in pronouns — as in he, him, his — and in irregular words such as think/thought, child/children, and mouse/mice.