How are cells with monosomy different from haploid cells

Haploid refers to a cell that has has only one copy of each chromosome, like in a gamete such as a sperm cell or egg cell. Upon fertilization, the two haploids come together to form a full diploid cell (two copies of each chromosome) which then goes on to form the complete organism. Monosomy refers to a condition where there is only one copy of a specific chromosome. For example, in the human condition Turner Syndrome, there is only one X chromosome, instead of two sex chromosomes. Most incidences of monosomy other than Turner Syndrome are lethal, so there aren't many examples of it.