Chromose = color, soma = body.
The chromosomes are those, following common tissue treatment methods, strongly colored X-like "pair formations" that occur during cell division. The members of pair formation are called chromatids and are connected in one place by the centromere. At the end of cell division, the chromatid pair is separated in such a way that one chromatid is placed in one of the two resulting daughter cells and the other chromatid in the other daughter cell. The chromatids are now called chromosomes (which is somewhat confusing), quickly lose colorability and after a short while can no longer be identified by standard tissue treatment methods.
An analysis of chromatids, when they appear at the beginning of cell division, shows that they consist of a several centimeter long DNA molecule (genetic material) ingeniously compressed and packaged in various egg whites, of which the so-called "histones" are the most important group.