Intervallit

Intervallit is the Finnish plural noun meaning intervals. In Finnish usage, the term covers a range of related concepts across disciplines, including mathematics, music theory and everyday measurement. It is a loanword from Latin intervallum and appears in Finnish as intervalli in the singular and intervallit in the plural.

In mathematics, intervallit denote segments of the real number line between two endpoints. They can be closed [a,b], open (a,b), or half-open [a,b) and (a,b]. Intervallit may be finite or infinite (for example [0,∞) or (-∞,0)). They are combined and manipulated through unions and intersections and serve as the basic building blocks of interval arithmetic and real analysis.

In music theory, intervallit refer to the pitch distance between two notes. Intervals are categorized by quality (perfect, major, minor, augmented, diminished) and by size (seconds, thirds, fourths, fifths, etc.). They form the foundation of melodies and harmonies and can be simple (within one octave) or compound (requiring more than an octave).

In other contexts, intervallit describe a span or range of values, time, ages or measurements. They appear in statistics and survey design when grouping data (for example age intervals such as 0–9, 10–19), and in common language to indicate any interval between two marks, events or quantities, such as time intervals between trains or measurement intervals in experiments.

See also: interval (mathematics), interval (music), time interval, confidence interval.