Verse is the ablative of the Latin term "versus the one” which means “turned, turned”. The word “back” designates the opposite side, the opposite page to the front or the inner side of the leaves of the plants.
In a poem, the verse corresponds to each of the lines that constitute it. It is the defining element of poetry as opposed to prose. A set of verses with full meaning is called a "stanza".
The verses give rhythm, melody and meter to a poem. They can be measured using metrification techniques and classified by the number of metric syllables (or poetic syllables). Metric syllables are different from grammatical syllables.
In Portuguese, the tone of words determines the number of metric syllables. The count of verse sounds goes down to the last stressed syllable of each verse. Example of 7-syllable verses (heptasyllable or Redondilha major):
In / that / it / naked / comes / in /what/la
Man/do/you/ my/ pen/sa/men/to
What / did / s / cu / pe / do / come/to
(Perfect Love Poem - Cecília Meireles)
Traditional (regular) verses can range from 1 to 12 or more metric syllables, obtaining the following classification: monosyllable (one syllable), disyllable (two syllables),..., dodecasyllable (12 syllables, also called Verses Alexandrians).
Verses with more than 12 syllables are called "Barbarian Verses".
Free (irregular) verses are those that do not have the same number of syllables in the poem, that do not follow a metric restriction.
See too: what is poem.