A volta is the turn in a poem, especially a sonnet, where the speaker shifts direction in thought, tone, argument, or feeling. In a sonnet, it often appears near the middle or near the end, marking a move from one idea to another, such as a problem to a response, a question to an answer, or a mood of despair to one of acceptance.
Example
I counted every loss the winter brought,
The empty branch, the silence by the door;
Then morning warmed the glass, and in that light
I saw one bud I had not noticed before.
[n] Italian physicist after whom the volt is named; studied electric currents and invented the voltaic pile (1745-1827)