Rhyme is the repetition of identical or similar sounds starting from the stressed vowel of two or more words, usually at the end of lines. In Portuguese, rhyme organizes the sound and creates a sense of rhythm and unity in the poem. Rhyming does not depend on identical spelling, but on sonic similarity. Verses that rhyme may appear together or be separated in the poem.

Perfect rhyme occurs when there is total coincidence of sounds from the stressed vowel onward, including consonants and the following vowels. This coincidence can happen with identical endings or different spellings in writing, as long as the sound is the same. Perfect rhymes are stable and predictable to the ear. They are widely used in songs and quatrains because they facilitate rhythm.

Assonant rhyme is the repetition of vowel sounds from the stressed vowel, even if the final consonants differ. The ear perceives similarity because the dominant vowel repeats at the end of the lines. This rhyme is also called vowel rhyme. Modern poems use assonant rhyme to avoid monotony and maintain musicality.

Consonant rhyme is a synonym for perfect rhyme in Portuguese: the stressed vowel and the following consonants coincide. The logic is that the entire final part of the sound repeats, not only the vowel. Therefore, "cantar" and "olhar" rhyme consonantly, while assonant rhyme accepts more variation. In analyses, "consonant" and "perfect" often indicate the same phenomenon.

Poor rhyme occurs between words of the same grammatical class and with common endings, such as two nouns in "-ão". Rich rhyme involves different classes or less predictable endings, increasing sonic variety. The classification does not judge beauty, but structure. Poets alternate poor and rich rhymes to balance naturalness and surprise.

Internal rhyme appears within the same line or between internal positions of lines, not only at the end. It creates sonic echoes that reinforce rhythm without relying on traditional cadence. Contemporary poems use internal rhyme for stylistic flexibility. The perception of internal rhyme depends on the proximity of sounds in the flow of the text.

Alternating rhyme organizes lines with the ABAB scheme, where the first and third lines rhyme with each other, and the second and fourth rhyme with each other. This pattern creates chaining and keeps the poem open to transitions. It is common in sonnets and in quatrains. The reader expects the sonic repetition every two lines.

Coupled rhyme uses the AABB scheme, where two consecutive lines share the same rhyme, then the next two form another rhyme. This format creates closed sonic blocks and a sense of quick closure. It is common in popular quatrains and songs. It can also appear within larger stanzas as segments.

Interpolated rhyme follows the ABBA scheme, where the first and fourth lines rhyme, and the second and third rhyme with each other. This arrangement creates a fitting effect, with the middle lines enclosed by the same rhyme. Portuguese sonnets tend to use interpolation in the quatrains. The pattern favors cohesion between the beginning and end of the stanza.

Poetic license allows adjusting pronunciation, syllable division, or word order to favor rhyme and rhythm in the poem. The poet may add or reduce syllables, bringing sounds closer that would be different in ordinary use. These choices work best when they maintain clarity and naturalness in context. The tradition of Brazilian poetry accepts licenses with moderation.

Rhyme in Portuguese is the repetition of sounds from the stressed vowel, seeking harmony between lines. Perfect rhyme repeats complete sounds; assonant rhyme highlights vowels. Schemes such as ABAB, AABB, and ABBA organize the distribution of rhymes. Poetic license allows small adaptations to maintain musicality without losing meaning.