interval

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A space between two objects, points, or units.
2. n. The amount of time between two specified instants, events, or states.
3. n. One of a series of predetermined distances covered at regular time increments with intermittent periods of rest in an athletic workout.
4. n. Mathematics A set of numbers consisting of all the numbers between a pair of given numbers along with either, both, or none of the endpoints.
5. n. Mathematics A closed interval.
6. n. Mathematics An open interval.
7. n. Mathematics A half-open interval.
8. n. Mathematics A line segment representing the set of numbers in an interval.
9. n. Chiefly British An intermission, as between acts of a play.
10. n. Music The difference, usually expressed in the number of steps, between two pitches.

Century Dictionary and Cyclopedia

1. n. A vacant or unobstructed space between points or objects; an intervening vacancy; an open reach or stretch between limits: as, the intervals between the ranks of an army.
2. n. Specifically, a low level tract of land, as along a river, between hills, etc. Also intervale.
3. n. Any dividing tract in space, time, or degree; an intervening space, period, or state; a separating reach or stretch of any kind: with reference either to the space itself or to the points of separation or division: as, an interval of rocky ground between meadows; to fill up an interval in. conversation with music; an interval of ease or of relapse in disease; a lucid interval in delirium; to set trees at intervals of fifty feet; to breathe only at long intervals; the clock strikes at intervals of an hour.
4. n. Specifically, in entomology, one of the spaces between longitudinal striæ of the elytra. When the striæ are regular, both they and the intervals are numbered from the suture outward.
5. n. In music, the difference or distance in pitch between two tones. If the tones are sounded simultaneously, the interval is harmonic; if successively, melodic. An interval is acoustically described by the ratio between the vibration-numbers of the two tones: thus, an octave is represented by the ratio 2:1; a fifth, by the ratio 3:2, etc. Musically the intervals between the key-note of a major scale and its several tones are regarded as the standards with which all possible intervals are compared and from which they are named. The standard intervals are as follows: do to do (C to C, F to F, etc.) is called a first, prime, or unison; do to re (C to D, F to G, etc.), a second; do to mi (C to E, F to A, etc.), a third; do to fa (C to F, F to B♭, etc.), a. fourth; do to do′ (C to C′ , F to F′ , etc.), an eighth or octave, etc. These intervals are usually further designated thus: standard firsts, fourths, fifths, and octaves are perfect; standard seconds, thirds, sixths, sevenths, ninths, etc., are major. If an interval is a half-step longer than the corresponding standard interval, it is called augmented (or sharp, superfluous, extreme, redundant): thus, do to fi (C to F♮, F to B♮, etc.) is an augmented fourth; do to li (C to A♮, F to D♮, etc.) is an augmented sixth. If an interval is a half-step shorter than the corresponding major interval, it is called minor (or flat): thus, do to me (C to E♭, F to A♭, etc.) is a minor third, etc. If an interval is a half-step shorter than the corresponding perfect or minor interval, it is called diminished: thus, do to sol♭ (C to G♭, F to C♭, etc.) is a diminished fifth (also called imperfect); di to le (C♮ to A♭, F♮ to D♭, etc.) is a diminished sixth, etc. (This nomenclature is obviously inconsistent, and another is also in use. according to which all standard intervals are called major, all a half-step longer than the corresponding major intervals are called augmented, all a half-step shorter than the corresponding major are called minor, and all a half-step shorter than the corresponding minor are called diminished.) A given interval is measured and named by comparison with a major scale based on the lower tone of the interval. Intervals not greater than an octave are called simple; those greater than an octave, compound compound intervals being reducible to simple ones by subtracting one or more octaves. When the upper tone of a simple interval is transposed an octave downward or its lower tone an octave upward, the interval is said to be inverted: inverted firsts become octaves, seconds become sevenths, thirds become sixths, etc.; and perfect intervals remain perfect, major intervals become minor, minor intervals become major, augmented intervals become diminished, and diminished intervals become augmented. Intervals are consonant or dissonant: the perfect consonances are standard firsts, fourths, fifths, and octaves; the imperfect consonances are major or minor thirds and sixths; and the dissonances are major or minor seconds and sevenths, with all augmented and diminished intervals. The acoustical values of the more important recognized intervals are as follows:
6. n. The values given in the first column are those of the ideal intervals, such as are secured by using pure intonation; those given in the second column are those of equally tempered intonation, such as is used on keyed instruments, like the pianoforte and the organ. (See intonation and temperament.) A diatonic, interval is one that occurs between two tones of a normal major or minor scale. A chromatic interval is one that occurs between a tone of such a scale and a tone foreign to that scale. An enharmonic interval is one on an instrument of fixed intonation, that is apparent only in the notation, being in fact a unison, as, on the pianoforte, the interval from F♮ to G♭. In musical science the theory of intervals is introductory to that of chords and to harmony in general.
7. n. In logic, a proposition.
8. n. During or between intervals; between whiles or by turns; occasionally or alternately: as, to rest at intervals.

Wiktionary

1. n. A distance in space.
2. n. A period of time.
3. n. music The difference (a ratio or logarithmic measure) in pitch between two notes, often referring to those two pitches themselves (otherwise known as a dyad).
4. n. mathematics A connected section of the real line which may be empty or have a length of zero.
5. n. chiefly UK An intermission.
6. n. sports half time, a scheduled intermission between the periods of play
7. n. cricket Either of the two breaks, at lunch and tea, between the three sessions of a day's play

GNU Webster's 1913

1. n. A space between things; a void space intervening between any two objects.
2. n. Space of time between any two points or events
3. n. A brief space of time between the recurrence of similar conditions or states
4. n. (Mus.) Difference in pitch between any two tones.
5. n. Local, U. S. A tract of low ground between hills, or along the banks of a stream, usually alluvial land, enriched by the overflowings of the river, or by fertilizing deposits of earth from the adjacent hills. Cf. bottom, n., 7.

WordNet 3.0

1. n. a definite length of time marked off by two instants
2. n. the difference in pitch between two notes
3. n. a set containing all points (or all real numbers) between two given endpoints
4. n. the distance between things