Source : Webster's Revised Unabridged Dictionary (1913)

Cater-cornered \Ca"ter-cor`nered\, a. [Cf. {Cater} to cut
   diagonally.]
   Diagonal. [Colloq.]

Source : WordNet®

cater-cornered
     adj : slanted across a polygon on a diagonal line; "set off in a
           catty-corner direction across the vacant lot" [syn: {catacorner},
            {cata-cornered}, {catercorner}, {catty-corner}, {catty-cornered},
            {kitty-corner}, {kitty-cornered}]