Rhymed lines that are usually of the same length and form a stanza are a poem. There are several stanza forms including the couplet, tercet, terza rima, quatrain, rhyme royal, ottava rima, Sonnet, Spenserian stanza, and others.
couplet
The poem "An Hymn to the Morning" by Phillis Wheatley utilizes a rhymed quatrain stanza form, with each stanza consisting of four lines.
Rhymed.
Couplets are a pair of lines of poetry that are usually rhymed and have the same meter. They often express a complete thought or idea within the two lines.
The poem "An Hymn to the Morning" by Phillis Wheatley is written in rhymed couplets, which is a stanza form where each stanza consists of two lines that rhyme.
In poems, irregular stanzas are usually those with different amounts of lines in each stanza. Whereas, regular stanzas are those with the same amounts of lines in each stanza. this usually gives the poem a song-like quality.
This is called "free verse" and resembles ungrammatical prose that has been broken into lines. It is designed, as is rhymed poetry, to impart meaning by the arrangement of words and concepts.
stanza
A quatrain is, in poetry, a specific type of poem. There are not many rules to follow, and writing a quatrain is fairly simple. The quatrain contains just four lines. That's it and that's all the rules for writing a quatrain.
Heptastich refers to a poem or stanza that has exactly seven lines. Each line in a heptastich can vary in length and meter.
A stanza of four lines is called a quatrain.
couplet