Abarim Publications' online Biblical Hebrew Dictionary
The root כדד (kdd) isn't used in the Bible but in cognate languages it may occur with the meaning of to toil severely or being very tired. In the Bible this root appears to have something to do with fire or glowing hot. The extant derivatives are:
- The feminine noun כד (kad), meaning jar (Genesis 24:14, Judges 7:16). The link between the verb and the noun possibly has to do with either the pounding and kneading of the mortar that will become a jar (see for instance Isaiah 41:25, " . . . even as the potter treads the clay . . . "), or the pounding and churning that goes on inside the jar. It is important to note that in the Bible, a jar is not some vessel that simply sits there, but an item that was brought about with great toil, and which continues to be associated with great toil. Our attention immediately turns to Adam's curse, who was to toil every day of his life (Genesis 3:17), and the name Adam literally means Corporeal or Clay Man. Jars play a very important role in Scriptures: from Gideon's campaign in Judges 7 (see v16) to Jesus' inaugurative miracle in Cana (John 2) and installation of the Communion rite (Mark 14:13). In Romans 9:21 Paul uses a metaphor that was one of Isaiah's favorites, "Or does not the potter have a right over the clay, to make from the same lump one vessel for honorable use, and another for common use?" (Romans 9:21). Isaiah said centuries before, "But now, O Lord, Thou art our Father, we are the clay and thou our potter, and all of us are the work of Thy hand". (Isaiah 64:8, also see 29:16 and 45:9)
- The masculine noun כידוד (kidod), possibly meaning spark, or else glow red hot. This noun occurs only in Job 41:11.
- The masculine noun כדכד (kadkod), denoting a kind of gem, possibly a ruby (Ezekiel 27:16 and Isaiah 54:12 only).