Easton's Bible Dictionary (1897)
This word is used of sediment found in pits or in streets (Isa. 57:20; Jer. 38:60), of dust mixed with spittle (John 9:6), and of potter’s clay (Isa. 41:25; Nah. 3:14; Jer. 18:1-6; Rom. 9:21). Clay was used for sealing (Job 38:14; Jer. 32:14). Our Lord’s tomb may have been thus sealed (Matt. 27:66). The practice of sealing doors with clay is still common in the East. Clay was also in primitive times used for mortar (Gen. 11:3). The “clay ground” in which the large vessels of the temple were cast (1 Kings 7:46; 2 Chr. 4:17) was a compact loam fitted for the purpose.
The expression literally rendered is, “in the thickness of the ground,”, meaning, “in stiff ground” or in clay.
Smith's Bible Dictionary (1863)
As the sediment of water remaining in pits or in streets, the word is used frequently in the Old Testament. (Psalms 18:42; Isaiah 57:20; Jeremiah 38:6) and in the New Testament, (John 9:6) a mixture of sand or dust with spittle. It is also found in the sense of potter’s clay. (Isaiah 41:25) The great seat of the pottery of the present day in Palestine is Gaza, where are made the vessels in dark-blue clay so frequently met with. Another use of clay was for sealing.
(Job 38:14) Our Lord’s tomb may have been thus sealed, (Matthew 27:66) as also the earthen vessel containing the evidences of Jeremiah’s purchase. (Jeremiah 32:14) The seal used for public documents was rolled on the moist clay, and the tablet was then placed in the fire and baked.
Hastings' Dictionary of the Bible (1898)
T. in the sense of ordinary mire in the streets, Ps 18:42; at the bottom of the sea, Isa 57:20; in a cistern or subterranean prison. Jer 38:6. e. potter's clay- Isa 41:25; Nah 3:14. T. the word "clay" is applied to a mixture of spittle with dust. John 9:6, Rev 1:11, 2 Sam 20:15. For the use of clay in brickmaking, see Brick; and in pottery, see Potter. Clay was also used for sealing. Job 38:14. Wine-jars, tombs, and doors were, and are, sealed with clay. See Seal.