The last two lines of a Shakespearean Sonnet are called a couplet. They are the only adjacent lines which rhyme with each other, the others rhyming alternately. In a Petrarchan sonnet the last two lines form part of a six-line unit called a sestet
There are two great families of sonnet types: the Italian and the Shakespearean.
An Italian sonnet splits its lines 8:6; in an Italian sonnet the final two lines don't have a specific name.
A Shakespearean sonnet splits its lines 4:4:4:2; the final two lines are called a COUPLET.
So the answer to your question is COUPLET; but only if you are talking about a Shakespearean sonnet.
There are 14 lines in a Shakespearean sonnet. The first twelve lines are divided into three quatrains with four lines each, and the final two lines are called a couplet.
If you are asking about an Elizabethan sonnet, it has 3 quatrains (ababcdcdefef) and a rhyming couplet (gg). If you are talking about a Petrarchan sonnet, the first section is called an octave (8 lines interrhymed--abbaabba) and the second section is called a sestet (six lines interrhymed--cdecde).
The sestet of an Italian sonnet consists of six lines. It typically follows the octave which has eight lines, making up the 14-line structure of the Italian (Petrarchan) sonnet.
There are fourteen lines, organized in three units of four lines called quatrains and a final couplet of two lines. In a Shakespearean sonnet the quatrains generally set up the situation and the couplet comments on it or sums it up. Sometimes Shakespeare wrote with a more Petrarchian setup, where the first eight lines set up the situation, and the last six take it in a different direction.
The last six lines of a sonnet are known as the sestet. In a Shakespearean sonnet, these lines typically follow a shift in tone or theme known as the volta. The sestet often presents a resolution or conclusion to the ideas presented in the first eight lines (the octave).
A couplet is found at the end of a sonnet. This consists of two lines that typically rhyme with each other and often serves to summarize the main idea or provide a twist or resolution to the poem.
An Italian sonnet is typically divided into two parts: an octave (first eight lines) and a sestet (final six lines). The octave usually presents a problem or question, with the sestet offering a resolution or answer. This structure allows for a shift in tone or content between the two sections of the poem.
"The Soote Season" is a Petrarchan sonnet because it follows the structure of an octave (eight lines) followed by a sestet (six lines). This sonnet form allows for the speaker to present a problem in the octave and then offer a resolution or reflection in the sestet.
Sonnet 75 by Edmund Spenser follows an ABABCC rhyme scheme in its octave (first eight lines) and a CDECE rhyme scheme in its sestet (last six lines).
A stanza with twenty lines is typically called a "sestet" or a "sestina." In traditional poetry forms like the sonnet or the villanelle, a sestet refers to a stanza with six lines.
A sestet is the name given to the second division of a Sonnet which must consist of an octave, of eight lines, succeeded by a sestet, of six lines.
Sonnet 29 by William Shakespeare explores feelings of isolation, self-doubt, and envy in the first eight lines, then pivots to a more positive and hopeful tone in the final six lines with themes of gratitude, acceptance, and the redemptive power of love and friendship. The shifting moods reflect the speaker's journey from despair to a place of solace and contentment.