Bible Dictionary
ONLY BEGOTTEN
Only begotten translates a term emphasizing uniqueness. In reference to Jesus, it describes His unique relationship with the Father, His revelation of God, and His role as the mediator of salvation; elsewhere it may mean an only child.
Biblical Usage
Applied to Christ, the term emphasizes that He uniquely reveals the Father and is the mediator of salvation. He is the Son in a sense unlike others, declares the unseen Father, and is sent so that people may live through Him. Elsewhere the word denotes an only son or daughter.