bar

In my post about bar mitzva, I wrote

bar בר means "son" (primarily in Aramaic, but also in Hebrew, see Mishlei 31:2)

The question is what is the connection between bar and the Hebrew word for son - בן ben? And does bar as "son" have a connection to any of the other meanings of the word bar, such as "outside", "pure" or "grain"?

In his entry for ben, Klein writes that

The change of n to r in Aramaic, Syriac, and Mehri is difficult to explain; it may be due to regressive dissimilation.

(See more detail in the article The Forms of 'Son' and 'Daughter' in Aramaic, by Steven Fassberg in the book Aramaic in its Historical and Linguistic Setting.)

Regarding the other meanings of bar, Klein doesn't connect them to "son", but does show how they are related to each other.  He discusses them all under the root ברר, meaning "to purify, select, set apart, separate". In his Hebrew etymological dictionary, he derives from this root the following words:

• bar בר - threshed grain or corn, from ברר (to purify, select)
• bar בר - pure, clean, related to ברר
• bor בור - lye, alkali, potash, from ברר. Related to another word for lye, borit בורית. Surprisingly, he makes no connection to "borax", which has the same meaning, but is of Persian origin (this book does connect the two).
• bar בר - exterior, outside. May have developed from another meaning of bar - "open field". Also related is the adverb bar, meaning "except, outside of". 
• beram ברם - but, however. A contraction of the Aramaic בר מא - "except what".
• baraita ברייתא - the Tanaitic sayings not incorporated in (excluded from) the Mishna.
• barur ברור - chosen; clear, distinct, certain
• borer בורר - arbitrator 

An English word with the same source is "barrio".  The Online Etymology Dictionary has the following:

"ward of a Spanish or Spanish-speaking city," sometimes also used of rural settlements, from Sp. barrio "district, suburb," from Arabic barriya "open country" (fem.), from barr "outside" (of the city). Main modern sense of "Spanish-speaking district in a U.S. city" is 1939; original reference is to Spanish Harlem in New York City.

It's worth noting that Stahl, in his Arabic etymological dictionary, disagrees with Klein, and connects bar as "son" with bar as "out". He notes the Hebrew word for "offspring, descendant", צאצא tze'etza, which derives from the root יצא - "to go out". So too does the child "go out" from his parents.

One other word that Klein thinks may be related to ברר is ברית brit (actually better spelled berit/b'rit, but that's not at all common) - "covenant". He writers:

Of uncertain etymology. Meyer derives it from ברה (= to eat bread); it would have been so called because in ancient times it was customary for those concluding a treaty or alliance to partake of a meal. Several scholars, with less probability, derive the noun ברית from ברה (= to choose.)

There's one more "bar" I didn't discuss, but I'll save that for the next post...