Recombination usually denotes a genetic event that occurs during the formation of sperm and egg cells (especially in areas of study of biology topics). It is also referred to as crossing over (or change of phase).

Other possible implication of the term are as follows:

• In biology, the process of Genetic recombination and meiosis, as summarized above.
• In chemistry and electrical engineering, it is the state in which the hydrogen and oxygen gases form within the battery cell during charging are recombined to form water.
• In cosmology, the event during which electrons became bound to nuclei. After recombination, ambient photons were no longer scattered but remain to the present as the Cosmic Microwave Background.
• In physics, Lord Kelvin's Knot theory describes atoms as knots of swirling vortices in the æther. This is helpful in understanding the mechanics of matter absorbing and emitting radiant energy, during reionization and ionization, in the Ionosphere.
• In evolutionary computing recombination is another name for crossover.