Heterotropic chromosome refers to a type of chromosome that is not directly involved in sex determination. However, there are several synonymous terms that can be used to describe a heterotropic chromosome. These include autosomal chromosome, non-sex chromosome, or somatic chromosome. These different terms are often used interchangeably and all refer to chromosomes that are not directly involved in determining the sex of an individual. In contrast, sex chromosomes, such as X and Y chromosomes, are directly responsible for determining the sex of an organism. Understanding the different terms used to describe different types of chromosomes is essential in genetics and biology.