Yachid (H3173) describes uniqueness and solitariness — being the only one, the singular beloved. It is the word used for Isaac as Abraham's 'only son' (Genesis 22) and for the beloved only child whose loss causes deepest grief. The LXX often translates it as agapetos (beloved) or monogenes (only-begotten).
Yachid creates one of Scripture's most powerful typological connections: Isaac as Abraham's yachid (Gen 22:2, 12, 16) prefigures Jesus as the Father's monogenes (John 3:16). Both sons are given up, carried to a mountain, bound (in type), and yet received back. The word carries the weight of deepest sacrificial love — giving the irreplaceable one.