Easton's Bible Dictionary (1897)
(Heb. kapporeth, a “covering;” LXX. ). It was of acacia wood, overlaid with gold, or perhaps rather a plate of solid gold, 2 1/2 cubits long and 1 1/2 broad (Ex. 25:17; 30:6; 31:7). It is compared to the throne of grace (Heb. 9:5; Eph. 2:6). The holy of holies is called the “place of the mercy-seat” (1 Chr. 28:11: Lev. 16:2).
It has been conjectured that the censer (thumiaterion, meaning “anything having regard to or employed in the burning of incense”) mentioned in Heb. 9:4 was the “mercy-seat,” at which the incense was burned by the high priest on the great day of atonement, and upon or toward which the blood of the goat was sprinkled (Lev. 16:11-16; comp. Num. 7:89 and Ex. 25:22).
Hastings' Dictionary of the Bible (1898)
MER'CY-SEAT was the name of the lid or cover of the ark of the covenant. It was made of gold, two and a half cubits long and one and a half cubits broad, and two cherubs, also of gold, were placed one at each end, stretching their wings toward each other, and forming a kind of throne, upon which God was believed to be present in a peculiar manner to hear and answer prayer, and to make known his holy will. Ex 25:17-22; Ex 30:6; Ex 31:7; Ex 37:6-9; 1 Chr 28:11; 2 Chr 6:7, 2 Chr 6:8;Ps 80:1; Ps 99:1.
Before and upon the mercy-seat the high priest sprinkled the blood of the sin-offerings on the day of atonement as a propitiation. Lev 16:11-16, which, under the new dispensation, received its typical signification. Heb 9:5; Rom 3:25. See Ark.