What term refers to the genetic makeup of an organism?

The term that refers to the genetic makeup of an organism is genotype. Genotype encompasses the specific alleles and genetic information an individual carries, which determines inherited traits. This is contrasted with phenotype, which refers to the observable characteristics or traits of an organism that result from the interaction of its genotype with the environment.

Karyotype refers to the number and appearance of chromosomes in the nucleus of a eukaryotic cell and can provide information about chromosomal abnormalities but does not specifically denote the genetic makeup of an organism at the level of specific genes. Chromatid describes one half of a replicated chromosome and is involved in cell division, but it does not refer to the overall genetic makeup.

Thus, genotype is the most accurate term to describe the entirety of an organism's genetic information.