The Collaborative International Dictionary of English v.0.48:

Shewbread \Shew"bread`\
   See Showbread.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Showbread \Show"bread`\, n. (Jewish Antiq.)
   Bread of exhibition; loaves to set before God; -- the term
   used in translating the various phrases used in the Hebrew
   and Greek to designate the loaves of bread which the priest
   of the week placed before the Lord on the golden table in the
   sanctuary. They were made of fine flour unleavened, and were
   changed every Sabbath. The loaves, twelve in number,
   represented the twelve tribes of Israel. They were to be
   eaten by the priests only, and in the Holy Place. [Written
   also shewbread.] --Mark ii. 26.
   [1913 Webster]

Easton's 1897 Bible Dictionary:

Shewbread
   Ex. 25:30 (R.V. marg., "presence bread"); 1 Chr. 9:32 (marg.,
   "bread of ordering"); Num. 4:7: called "hallowed bread" (R.V.,
   "holy bread") in 1 Sam. 21:1-6.

     This bread consisted of twelve loaves made of the finest
   flour. They were flat and thin, and were placed in two rows of
   six each on a table in the holy place before the Lord. They were
   renewed every Sabbath (Lev. 24:5-9), and those that were removed
   to give place to the new ones were to be eaten by the priests
   only in the holy place (see 1 Sam. 21:3-6; comp. Matt. 12:3, 4).

     The number of the loaves represented the twelve tribes of
   Israel, and also the entire spiritual Israel, "the true Israel;"
   and the placing of them on the table symbolized the entire
   consecration of Israel to the Lord, and their acceptance of God
   as their God. The table for the bread was made of acacia wood, 3
   feet long, 18 inches broad, and 2 feet 3 inches high. It was
   plated with pure gold. Two staves, plated with gold, passed
   through golden rings, were used for carrying it.