overmount

from The Century Dictionary.

• To surmount; go higher than.
• noun In framing or mounting pictures to be covered with glass, a piece of stiff paper or board cut to correspond with the margin of the engraving or picture to be mounted, and laid upon the picture to separate its surface from the glass in the frame; a mat.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To mount over; to go higher than; to rise above.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To mount over; to go higher than; to rise above.