Boyd’s Bible Dictionary:
(high). First altars were simple memorial piles (Gen. 8:20; 12:7; 26:25; 35:1). Afterward to lay sacrifices upon (Ex. 17:15-16; 27:1-8). Usually built of earth or stone (Ex. 20:24-26); but sacrificial altars quite elaborate (Ex. 40:26-33). Still more elaborate in Solomon’s Temple (1 Kings 8:64; 2 Chron. 7:7). Altar fires to burn perpetually (Lev. 6:12-13). Altar of Incense, called “golden” to distinguish it from Altar of Sacrifice, called “brazen” (Ex. 30:1-10; 40:5, 1 Kings 7:48; 1 Chron. 28:18).
Concise Bible Dictionary:
A structure on which to offer sacrifices to God: imitated by the heathen in honor of their false gods. The first altar we read of was built by Noah on leaving the ark, on which he offered burnt offerings of every clean beast and clean fowl (Gen. 8:20). Abraham, Isaac and Jacob also built altars to the Lord: these would have been constructed of stone or earth, but it is remarkable that we seldom read of their offering sacrifices on them. At times it is simply said they built an altar unto the Lord and at other times they built an altar and called upon the name of the Lord. The altars appear to have been erected as places of drawing near to God, of which sacrifice was the basis.
Moses was told that in all places where God recorded His name they should build an altar of wood or of stone and offer thereon sheep and oxen for burnt offerings and peace offerings; but such altars if made of stone were not to be made of hewn stone; for had they lifted up a tool upon it, it would have been defiled (Ex. 20:25-26). There must be nothing of man’s handiwork in approaching to God: a principle, alas, grossly violated in the professing church of God! It is added, “neither shalt thou go up by steps unto mine altar, that thy nakedness be not discovered thereon.” Man’s contrivance is here forbidden, for in divine things anything of his only manifests the utter shamelessness of that which springs from fallen nature (compare Col. 2:20-23). When the tabernacle was made, minute instructions were given to Moses, and he was to make everything as had been shown him in the mount.
Strong’s Dictionary of Greek Words:
Meaning:
from the base of 939; properly, a stand, i.e. (specially) an altar