MBS, or Mortgage-Backed Security, is an investment vehicle that is backed by home loans. It is a type of security that is created from a pool of mortgage loans that are then sold to investors. Synonyms for MBS include mortgage bonds, mortgage-backed notes, and mortgage pass-through certificates. These all refer to similar investment vehicles that are created from pools of mortgages. The market for MBS can be volatile as it is often correlated to changes in interest rates and the broader housing market. However, they can offer investors a relatively stable source of income and capital appreciation over the long term.