mortgage-backed security: a security created when a group of mortgages are gathered together and bonds are sold to other institutions or the public; investors receive a portion of the interest payments on the mortgages as well as the principal payments; usually guaranteed by the government
security: a formal declaration that documents a fact of relevance to finance and investment; the holder has a right to receive interest or dividends
millenary: a sum or aggregate of one thousand (especially one thousand years)