inflection

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act of inflecting or the state of being inflected.
• noun Alteration in pitch or tone of the voice.
• noun An alteration of the form of a word by the addition of an affix, as in English dogs from dog, or by changing the form of a base, as in English spoke from speak, that indicates grammatical features such as number, person, mood, or tense.
• noun An affix indicating such a grammatical feature, as the –s in the English third person singular verb form speaks.
• noun The paradigm of a word.
• noun A pattern of forming paradigms, such as noun inflection or verb inflection.
• noun A turning or bending away from a course or position of alignment.

from The Century Dictionary.

• noun In eccles. chanting, same as accent, 7.
• noun The act of inflecting, or the state of being inflected; a bend or bending.
• noun In optics, the peculiar modification or deviation which light undergoes in passing the edges of an opaque body, usually attended by the formation of colored fringes: more commonly called diffraction.
• noun In grammar, the variation of nouns, etc., by declension, and of verbs by conjugation; more specifically, variation in part by internal change, and not by added elements alone.
• noun Modulation of the voice in speaking, or any change in the pitch or tone of the voice in singing.
• noun In geometry, the place on a curve where a tangent moving along the curve by a rolling motion changes the direction of its turning, and begins to turn back; a stationary tangent.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of inflecting, or the state of being inflected.
• noun A bend; a fold; a curve; a turn; a twist.
• noun A slide, modulation, or accent of the voice.
• noun (Gram.) The variation or change which words undergo to mark case, gender, number, comparison, tense, person, mood, voice, etc.
• noun Any change or modification in the pitch or tone of the voice.
• noun A departure from the monotone, or reciting note, in chanting.
• noun (Opt.) Same as Diffraction.
• noun (Geom.) the point on opposite sides of which a curve bends in contrary ways.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

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

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a manner of speaking in which the loudness or pitch or tone of the voice is modified
• noun a change in the form of a word (usually by adding a suffix) to indicate a change in its grammatical function
• noun deviation from a straight or normal course
• noun the patterns of stress and intonation in a language