Chromatids are replicated chromosomes that are connected at the centromere. Synonyms for chromatids include sister chromatids, chromosome arms, chromosome strands, and double-stranded chromosomes. Sister chromatids are identical copies of each other that are formed during DNA replication and remain attached until cell division. Chromosome arms refer to the sections of the chromosome that are connected by the centromere. Chromosome strands and double-stranded chromosomes both describe the double helix structure of the DNA molecule that makes up the chromatids. Understanding the different terminologies used to describe chromatids is essential to studying mitosis and meiosis, which are cellular processes that involve the separation of chromatids.