Music is a vast arrangement of small sections, each divided into smaller sections, which are divided as well, et cetera. All of these little ideas are what form a complete musical thought. The smallest figure, melody-wise, is the motive (motif). It is simply a short figure which recurs throughout a passage or composition upon which the entire melody is built. A motive can generally be distinguished from a phrase or a theme by its length. Motives tend to be less than one measure long, for they are just like a small cell in the vast musical body.

A phrase is a larger musical thought, usually with a formal beginning and a formal closing. The length, and the presence of a cadence, is what distinguishes it from a motive. phrases usually run around 4 measures long, or so (they could be as many as 16 or as few as 2 measures long.) Phrases will often be broken into two parts, by a rest or a longer note. These broken pieces of the phrase are called phrase members. The phrase members are usually two contrasting statements, which together form a complete thought, but sometimes the second phrase member may simply be a repeat or an altered form of the first.

Two or more adjacent phrases form what is known as a period. Usually, an authentic cadence ends a period, and the first phrase will end with a weaker cadence than the last phrase. The most popular example of a period is the typical "call and answer" formula. In musical terms, the first phrase (call/question) is called the antecedent. The second phrase (answer) is called a consequent. The two phrases are forming one single idea, the first phrase does its part and finishes, but allows the movement of the song to continue (by using a weaker cadence) and the second phrase moves in and finishes up the thought (with a strong cadence.) Repeated phrases are not generally considered to form a period, whether they are identical or modified, because the second phrase is not (generally) dependent upon the first.

A sequence is an immediate restatement of melodic material in the same part (instrumental or vocal) at a different pitch so that the structure of the material is not changed. Each restatement of the material is called a segment. A sequence requires at least two segments (original and repeated) and should rightfully contain no more than four or five segments. Sequences generally have a single motion, either ascending or descending. There are two types of sequences: real and tonal. In a tonal sequence, the notes simply move up the scale, and remain within the key. An example would be: in the key of F-- Bb C D E (original segment), C D E F (repeated, staying within the key.) The real sequence demands that the intervals between the notes stay the same. For instance: in the key of F-- Bb C D E (original segment), C D E F# (real sequence). Granted, F# is not in the key of F, but I was forced to follow the WWWW formula I set up in the original.