The name Ben-oni in the Bible
Etymology of the name Ben-oni
The name Ben-oni obviously consists of two parts, the first one being the common Hebrew word בן (ben), meaning son:
The second part of the name Ben-oni comes from the remarkable root group און ('wn), meaning either sorrow or vigor:
The added letter י (yod) turns the word און ('on) into אוני ('oni), meaning my on.
Traditionally — and subscribed to by Jones' Dictionary of Old Testament Proper Names, BDB Theological Dictionary and NOBSE Study Bible Name List to list a few — the name Ben-oni is said to mean Son Of My Sorrows, taking the meaning of און ('awen) meaning trouble.
But this interpretation seems at odds with the events surrounding the naming of Ben-oni. His mother Rachel died when giving birth, so she surely must have felt troubled, but if she wanted her son to be a reminder of these labor-troubles, she would have picked a different word than און ('awen).
Remember that Rachel used to be deeply grieved for not having children (Genesis 30:1). It is highly unlikely that she would name her youngest son in such a way that the boy would be continuously reminded that he was the cause of his mother's death.
In addition to this, Jacob dearly loved Rachel. He spend 14 years of his life working to earn her (Genesis 29:20-30). It is highly unlikely that he would expunge Rachel's final act and her dying wish, and name the boy something completely different, yet still with the segment ben.
In stead, Rachel may have sought consolation that her son made it alive, just as the midwife says, "Do not fear, for now you have another son," and named him with the word און ('on).
We can not be certain how the ancient text of the Torah was pronounced. Yet from history we have received two ways to pronounce the word און: 'awen, in which the letter waw is considered a consonant, and on in which the waw is considered a vowel. Waw-vowel is a completely different letter than waw-consonant, and thus און ('awen) is a completely different word than און ('on).
The traditional pronunciation of the name Ben-oni strongly suggests that it was derived from 'on and not from 'awen,and that און means vigor and not sorrow.
All things considered, it seems most likely that when Rachel dies, Jacob doesn't simply rename the boy. Instead he respectfully amplifies the name that his wife had given him. This Son Is My Progeny (Ben-oni) becomes This Son Is Strength (Benjamin).