What does "inflection" mean?

Additional senses

1. 2.A slide, modulation, or accent of the voice; as, the rising and the falling inflection.
2. 3.(Gram.) The variation or change which words undergo to mark case, gender, number, comparison, tense, person, mood, voice, etc.
3. 4.(Mus.) (a) Any change or modification in the pitch or tone of the voice. (b) A departure from the monotone, or reciting note, in chanting.
4. 5.(Opt.) Same as Diffraction. Point of inflection (Geom.), the point on opposite sides of which a curve bends in contrary ways.