n.1. Change from one form, state, style, or place to another.
2. a. Change from one subject to another in discourse.
b. A word, phrase, sentence, or series of sentences connecting one part of a discourse to another.
3. Music a. Change from one key or tonality to another.
b. A passage connecting two themes or sections, usually changing to a new key or tonality.
4. Genetics A point mutation in which a pyrimidine is replaced by another pyrimidine, or a purine is replaced by another purine.
5. Sports The process of changing from defense to offense or offense to defense without a stoppage in play, as in basketball or hockey.
6. A period during childbirth that precedes the expulsive phase of labor, characterized by strong uterine contractions and nearly complete cervical dilation.