Abarim Publications' online Biblical Hebrew Dictionary
The root שבל (sbl) occurs all over the Semitic language spectrum, but since it's not used as verb in the Bible, it's not clear what it may have meant in Hebrew. Judging from the derivatives, the central meaning of this root is probably something like to extend or go forth in an undulating way:
Its derivatives are:
- The masculine noun שבל (shobel), denoting a kind of flowing garment (Isaiah 47:2 only).
- The feminine noun שבלת (shibboleth) denoting a flowing stream (Judges 12:6, Psalm 69:2 and 69:15, and Isaiah 27:12 only). This or the next word was used by the men of Gilead to identify men of Ephraim (Judges 12:6).
- The identical feminine noun שבלת (shibbolet), meaning ears of grain (Job 24:24). The masculine version שבלים (shibbelim) occurs in Genesis 41:5-27, Ruth 2:2 and Isaiah 17:5. Other verbs that mean flow also yield nouns that have to do with produce. Produce was probably seen as "flowing" from the land.
- The masculine noun שבול (shebul) or שביל (shebil), meaning way or path (Psalm 77:19, Jeremiah 18:15 only).
Note the parallels between the verbs שבל (sbl) and יבל (yabal)