Conversion Rule. If you convert money from a tax-deferred retirement account to a Roth IRA, you must wait at least five years before taking distributions of the converted amounts to avoid the 10 percent early withdrawal penalty. However, you won't pay income taxes on the distribution, because you paid them on the conversion.
Freebase(0.00 / 0 votes)Rate this definition: Polysomy. Polysomy is a condition in which an otherwise diploid organism has at least one more chromosome than normal, i.e. the number of a particular chromosome is not diploid - there may be three or more copies of the chromosome rather than the expected two copies.
â¢ TRISOMY (noun). The noun TRISOMY has 1 sense: 1. chrosomal abnormality in which there is one more than the normal number of chromosomes in a cell. Familiarity information: TRISOMY used as a noun is very rare.ypernyms (trisomy is a kind of...): chromosomal aberration; chromosomal anomaly; chromosonal disorder; chrosomal abnormality (any change in the normal structure or number of chromosomes; often results in physical or mental abnormalities). Hyponyms (each of the following is a kind of trisomy):