Abarim Publications' online Biblical Hebrew Dictionary
אב
In Hebrew the word אב ('ab) is the proper word for father, but it comes from an assumed root אבה ('bh). What that root (verb) may have meant to the Hebrews, we don't know because it's not used in the Bible, and that means we have no context to try it to. BDB Theological Dictionary is even less yielding and declares this root "perhaps at least formally justified as the stem of אב ('ab), but existence and meaning wholly dubious". But, sayeth BDB in the shortest abbreviations justifiable, there is an Assyrian verb abu, which means to decide. The 'ab would thus be the one who decides.
And then, to make matters worse, there's the verb אבה ('aba), which is spelled and pronounced identical to the assumed root of אב ('ab). This verb is quite common in the Bible, and it means to accede to a wish, consent or accept to a reproach. HAW Theological Wordbook notes, "The primary meaning of this root is the willingness (inclination) to do something under obligation or upon request".
This latter verb is spelled identically to the verb בנה (bana), to build, which clearly associates to the noun בן (ben), son (hence the familiar metaphor of sons as stones that build the house: 1 Peter 2:5). This latter noun combined with our word for father gives the noun אבן ('eben), meaning stone.
Also identical to our word for father is the word אב ('eb), which means freshness or fresh green, from the assumed root אבב ('bb). Another derivation of this root is the word אביב ('abib), meaning barley. Hence the name Tel Aviv.
The plural of our word for father, namely אבות ('abot), fathers, is spelled identically to the plural of the word אוב ('ob), which appears to describe an instructor, mentor or tutor and became the word for medium or spirit (or witch).
Our noun אב ('ab), father, occurs often in meanings other than that of a biological parent. Sometimes it's used to indicate the lord of a village (Isaiah 22:21), or an elder (2 Kings 2:12), or an ancestor (Genesis 10:21), and often it simply indicates a position of authority; a counselor (Genesis 45:8) or prophet (2 Kings 6:21). The word 'ab is also ascribed to God (Isaiah 63:16, Hosea 11:1)
It stands to reason that the word אב ('ab) is not, like our word "father" reserved for the male parent and used metaphorically for other people, but rather a word of unknown and unparalleled meaning, which expresses respect to persons of authority, including male parents.
The word 'ab followed by the letter yod usually makes the ab-part possessive. The construct אבי ('abi) may mean "father of," "my father," or form the adjective fatherly (literally "of father").
Also note the following structure, and remember that a man's "house" is not simply a building but rather his wife and children:
- The noun אב ('ab) means father and possibly comes from the root אבה ('bh). A verb spelled and pronounced exactly the same as the assumed root of the word אב ('ab) is the verb אבה ('aba), meaning to do something under obligation or upon request.
- The noun בן (ben) means son and probably comes from the verb בנה (bana) meaning to build, such as a house. From בן (ben) in turn comes the word בת (bat), which means daughter. Linguistically unrelated but still striking is the word בית (bayit, or beth in constructs such as Bethel or Bethlehem), which means house. And equally unrelated but still striking is the verb בין (bin), literally meaning being able to see a difference; perceive or discern. A derivative of this verb is the substantive בין (ben), meaning between.