Base Offering Circular - Single Family 49 Class Principal Balance .............................  As  to  any  Class  other  than  a  Notional  Class  as  of  any  Distribution Date,  the  Original  Class  Principal  Balance  of  that  Class  less  all payments   of   principal   previously   allocated   to   that   Class   (plus amounts,  if  any,  added  to  the  Class  Principal  Balance)  on  previous Distribution   Dates,   except   as   otherwise   provided   in   the   related Offering Circular and Trust Agreement or MX Trust Agreement, as applicable. Class R Security ........................................  A Security that represents a Residual Interest in a Trust REMIC. Class RI Security.......................................  A Security that represents a Residual Interest in an Issuing REMIC. Class RP Security ......................................  A Security that represents a Residual Interest in a Pooling REMIC. Class RR Security......................................  A  Security that represents a  Residual Interest in two or  more Trust REMICs. Class Type.................................................  An Interest Type, Principal Type or Other Type. Closing Date..............................................  For  each  Series,  the  date  upon  which  the  Sponsor,  pursuant  to  the Trust Agreement or MX Trust Agreement, as applicable, deposits the Trust  Assets  in  the  Trust  or  MX  Trust,  as  the  case  may  be,  in exchange for the Securities and settles for the Securities. Closing Documents ...................................  With respect to each Series, those documents, specified in the related Sponsor  Agreement,  that  are  to  be  executed  by  the  parties  to  the transaction on or before the Closing Date. Code ..........................................................  The Internal Revenue Code of 1986, as amended. COFI..........................................................  The weighted average cost of funds for member savings institutions of the Eleventh Federal Home Loan Bank District. COFI Class ................................................  A Class bearing interest at a rate determined by reference to COFI. Combination..............................................  Any  permitted  combination  of  REMIC  and/or  MX  Securities  set forth in an Available Combinations Schedule. Component ................................................  With respect to any Component Class, one of the component parts of such  Class.    The  Components  of  a  Component  Class  may  have different  principal  and/or  interest  distribution  characteristics,  but together   they   constitute   a   single   Class   and   are   not   separately transferable   from   the   related   Class.      Each   Component   may   be categorized according to one or more Class Types. Component Class.......................................  A Class composed of Components. Component Principal Balance ...................  As to any Component other than any Notional Component as of any Distribution Date, the Original Component Principal Balance of that Component less all principal previously allocated to that Component (plus  Accrual  Amounts,  if  any,  added  to  the  Component  Principal Balance)   on   previous   Distribution   Dates,   except   as   otherwise provided in the related Offering Circular and Trust Agreement. Corporate Trust Office ..............................  With respect to a Series, the  meaning specified in the related Trust Agreement.