Recombination: Recombination can have slightly different meanings depending on context:

1. In the context of genetic crosses (usually a dihybrid crossplugin-autotooltip__default plugin-autotooltip_bigDihybrid cross: a cross, developed by Gregor Mendel, that illustrates Mendel's Second Law. See Chapter 03. or a test crossplugin-autotooltip__default plugin-autotooltip_bigTest cross: a genetic cross devised by Gregor Mendel that allows a researcher to easily determine the genotype of an individual that appears wildtype but has an unknown genotype. This assumes you have a tester strain readily available. See Chapter 03.), recombination refers to the phenomena where the phenotypeplugin-autotooltip__default plugin-autotooltip_bigPhenotype: an observable feature or property of an organism. of the F2 offspring is different than either parent (P generation).
2. In the context of non-sister chromatidsplugin-autotooltip__default plugin-autotooltip_bigNon-sister chromatids: Chromatids that are derived from two different chromosomes in a homologous chromosome pair during meiosis I. See also: sister chromatids., recombination refers to crossing overplugin-autotooltip__default plugin-autotooltip_bigCrossing over: an event where non-sister chromatids exchange material with each other during meiosis I. (which can result in recombination in the sense of the first definition.
3. In the context of molecular biologyplugin-autotooltip__default plugin-autotooltip_bigMolecular biology: the study of nucleic acids, specifically DNA and RNA., recombination refers to exchange of DNAplugin-autotooltip__default plugin-autotooltip_bigDNA: deoxyribonucleic acid. The genetic material for nearly all life on Earth. between different DNAplugin-autotooltip__default plugin-autotooltip_bigDNA: deoxyribonucleic acid. The genetic material for nearly all life on Earth. molecules, e.g., in the Creplugin-autotooltip__default plugin-autotooltip_bigCre-$lox$ system: A site-specific DNA recombination system derived from bacteriophage P1. The enzyme Cre recombinase will drive DNA recombination between 34 bp-long $loxP$ sequences. Very commonly used in various reverse genetic experiments.-$lox$ system.