They are both cell divisions but there are major differences betwenn them. First of all, meiosis only happens in sex cells (egg cells in women and sperm cells in men) and is a reduction diviosion, i.e. the amount of genetic material halves while it stays the same in mitosis. The reason for this is that the amount of genetic material must pe preserved in each generation (meioisis ensures it doesn't double with each generation).

Also, there are two divisions in meiosis yeilding 4 daughter cells and just one in mitosis producing 2 cell.