Definition of artificial chromosome in US English:

artificial chromosome

noun

Biology
  • (Originally) a synthetic nucleic acid sequence designed to mimic the structure and behaviour of a chromosome; (now usually) a nucleic acid sequence into which an artificial or modified gene, or a fragment of a natural genome which is being studied, can be maintained, reproduced, and manipulated within a carrier such as a bacterial or yeast cell.

Origin

1980s; earliest use found in Nature: a weekly journal of science.