There are several variations of Down syndrome with Trisomy 21 accounting for close to 95% of all cases recorded. There is another form of the syndrome that occurs when a segment of the 21st chromosome detaches to attach itself to another chromosome. Its name is

The correct option is Translocation.

Down syndrome is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. While Trisomy 21 (where there are three independent copies of chromosome 21 in every cell due to nondisjunction during meiosis) is the most common cause, accounting for about 95% of cases, other genetic mechanisms can lead to the syndrome.

One such variation is translocation (specifically, Robertsonian translocation). This occurs when a segment or the entirety of chromosome 21 detaches and attaches itself to another chromosome (most commonly chromosome 14). Because the genetic material of chromosome 21 is still present in triplicate (two normal copies of chromosome 21 plus the translocated portion on another chromosome), the individual develops the characteristics of Down syndrome.

Let's briefly define the options to see why "Translocation" is the correct term:
- Translocation: In genetics, this refers to a rearrangement of parts between nonhomologous chromosomes. This is the precise scientific term for a chromosome segment transferring to another chromosome.
- Displacement, Transportation, and Relocation: These are general, non-biological terms that are not used to describe structural chromosomal mutations.