Recombination can refer to various processes in different fields which include biology, chemistry, physics, astronomy, and computing.
Biology
In biology, recombination usually refers to genetic recombination and meiosis, a genetic event that occurs during the formation of sperm and egg cells. It is also referred to as crossing over or change of phase. In addition to its use in meiosis in eukaryotic cells, recombination is used to repair DNA double-strand breaks and to recover stalled DNA replication forks in Eukarya, Archaea, and Eubacteria. Recombination, then, like DNA replication, RNA transcription, and protein translation, is one of the most ancient cellular processes on Earth.
Chemistry
In chemistry, it is the state in which the hydrogen and oxygen gases which form within the battery cell during charging are recombined to form water.
Physics
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 solid state physics of semiconductors, carrier recombination is a process by which electrons and electron holes are mutually eliminated, and is balanced with carrier generation to establish the carrier density at thermal equilibrium.
Astronomy and Cosmology
In physical cosmology, the event after the Big Bang during which electrons became bound to nuclei. After the decoupling of matter and radiation, which happened at about the same time as recombination, ambient photons could travel freely, and are visible today as the Cosmic Microwave Background.
It can also refer to to an electron becoming bonded with an ionized atom as in both Astronomy and atomic physics.
Computing
In evolutionary computing, recombination is another name for crossover.