Boyd’s Bible Dictionary:
(1) Hollow vessel of wood or stone, in which corn was ground with a pestle (Num. 11:8; Prov. 27:22). (2) Various cementing substances used in building, as bitumen, clay, and ordinary mixture of sand and lime (Gen. 11:3; Ex. 1:14; Lev. 14:42; Isa. 41:25).
Concise Bible Dictionary:
Stone Mortar and Pestle
The monuments of Egypt show that anciently, as now, stone mortars with stone pestles were used for pounding hard seeds. The manna was ground in mills or beaten in a mortar (Num. 11:8). Though by this means the seeds were pounded very small, yet even such treatment would not cure a fool of his folly: it shows the incorrigible nature of him who despises wisdom and instruction (Prov. 27:22).
Strong’s Dictionary of Hebrew Words:
From Manners and Customs of the Bible:
Leviticus 14:42. He shall take other mortar, and shall plaster the house.
There were several kinds of mortar used by the Hebrews. Sometimes they used common mud and clay, mixed with straw chopped and beaten small. This may have been the kind especially referred to in the text. Aphar, “mortar,” is frequently rendered “dust,” and indeed is so translated in the verse preceding, where reference is made to the coating of old mortar which was scraped from the outside of the house. They also had several varieties of calcareous earth, any of which, mixed with ashes, made a good mortar. They likewise prepared an excellent cement of one part sand, two parts ashes, and three parts lime. These ingredients were well pounded, and were sometimes mixed with oil, while at other times the oil was put on as an outer coating.
Mortar was usually mixed by being trodden with the feet, but wheels were sometimes used.