For the beginning songwriter, it may be helpful to know something about the various elements of a song. Following are some definitions:
Melody: the part of a song that can be sung alone so that the song is recognizable; the "lead". 
Elements of the melody include:
Elements of the melody include: Motif: a short group of notes. Phrase: Two motifs combined. Sentence or period: Two phrases combined. Paragraph: A group of sentences. Sequence: a melodic phrase that is repeated but is transposed.Harmony: the notes that support the melody. These may be sung or played.
Rhythm: the pattern of beats to which the words are sung.
Tempo: the speed of the song.
Time Signature: 3/4, 4/4, 6/8, etc.
Intro: the short instrumental section at the beginning of the song.
Verse: a section of the song having its own melody, usually following the introduction and occurring again after the chorus. Most songs have two or three verses, repeating the same melody with different words. Verses usually have about eight measures.
and occurring again after the chorus. Most songs have two or three verses, repeating the same melody with different words. Verses usually have about eight measures.Chorus: a different section in the song with a different melody, usually following the verses and the bridge. The chorus may be very repetitive.
verses and the bridge. The chorus may be very repetitive. Bridge: a section of the song that is different from the verses and chorus. The bridge usually occurs during a transition between verse and chorus or between two choruses in separate keys; hence, it is called the "bridge".
usually occurs during a transition between verse and chorus or between two choruses in separate keys; hence, it is called the "bridge". Hook: an important phrase in the song, the theme. The hook is usually repeated at various times during the song. Also referred to as the motif.
various times during the song. Also referred to as the motif.Coda: the end of the song; usually repeats the hook or an important portion of the song.
