The term 'sonnet end' is composed of two crossword solutions, SESTET (6 letters) and EER (3 letters). A sestet is a six-line stanza in a poem, usually the last six lines of a sonnet. An eer is a three-letter word meaning 'a unit of energy equal to the work done by a force of one dyne when its point of application moves through a distance of one centimeter in the direction of the force'. Therefore, the term 'sonnet end' can be defined as the last six lines of a sonnet, which are typically used to summarize the poem's main idea or provide a resolution.