Boyd’s Bible Dictionary:

(showbread). Unleavened bread baked in twelve loaves corresponding to the twelve tribes, and placed fresh every Sabbath on the golden table of the sanctuary. Eaten only by the priests (Ex. 25:30; Lev. 24:8; 1 Sam. 21:1-6; Matt. 12:3-4). The arrangement of loaves on the table was in two rows of six loaves each. Salt and frankincense were put on each row. It was called “showbread,” “bread of the face,” or “bread of the setting before,” because it stood continually before the Lord. In later times it was called the “bread of ordering” (1 Chron. 9:32 marg.; Neh. 10:33).

Concise Bible Dictionary: