copy number alterations

Definition of copy number variant
National Cancer Institute

copy number variant

(KAH-pee NUM-ber VAYR-ee-unt)
Refers to the genetic trait involving the number of copies of a particular gene present in the genome of an individual. Genetic variants, including insertions, deletions, and duplications of segments of DNA, are also collectively referred to as copy number variants. Copy number variants account for a significant proportion of the genetic variation between individuals. Also called CNV.

Source: NCI Dictionary of Cancer Terms