Easton's Dictionary
An instrument only referred to in connection with the custom of
boring the ear of a slave (Ex. 21:6; Deut. 15:17), in token of
his volunteering perpetual service when he might be free. (Comp.
Ps. 40:6; Isa. 50:5).
Smith's Dictionary
a tool of which we do not know the ancient form. The only notice of it is in connection with the custom of boring the ear of the slave. (Exodus 21:6; 15:17)
International Standard Bible Encyclopedia
ol martsea`: "Bore his ear through with an awl" (Ex 21:6; De 15:17). The ear was pierced as being the organ of hearing, thus signifying the servant's promise of obedience. See BORE.