Backer n. : One who, or that which, backs; especially one who backs a person or thing in a contest.

Example:
Whats the best/easy way to cut Backer board for bathroom tile?

Taxonomy
Backer, free encyclopedia, Search, Augustin de Backer, Brian Backer, Harriet Backer, Jacob de Backer, Jacob Adriaensz Backer, Lars Backer, P. A. Backer, Agathe Backer-Grøndahl, given name, Norwegian pianist, Norwegian painter, Norwegian architect, free dictionary, Norwegian, Roman Catholic.

Defination from the web:
Backer (1809–1873), Roman Catholic bibliographer. Brian Backer (born 1956), American actor. Harriet Backer (1845-1932), Norwegian painter ... Jacob de Backer (c. 1555 – c. 1585), Flemish Mannerist painter and draughtsman. Jacob Adriaensz Backer (1609-1651), Dutch painter ...