Definition (full): a relative by marriage, a circumcised child
Strong's Exhaustive Concordance
From chathan; a relative by marriage (especially through the bride); figuratively, a circumcised child (as a species of religious espousal) -- bridegroom, husband, son in law.
KJV: And the men said unto Lot, Hast thou here any besides? son in law, and thy sons, and thy daughters, and whatsoever thou hast in the city, bring them out of this place:
NASB: Then the two men said to Lot, "Whom else have you here? A son-in-law, and your sons, and your daughters, and whomever you have in the city, bring them out of the place;
KJV: And Lot went out, and spake unto his sons in law, which married his daughters, and said, Up, get you out of this place; for the LORD will destroy this city. But he seemed as one that mocked unto his sons in law.
NASB: Lot went out and spoke to his sons-in-law, who were to marry his daughters, and said, "Up, get out of this place, for the LORD will destroy the city." But he appeared to his sons-in-law to be jesting.
KJV: Now Moses kept the flock of Jethro his father in law, the priest of Midian: and he led the flock to the backside of the desert, and came to the mountain of God, even to Horeb.
NASB: Now Moses was pasturing the flock of Jethro his father-in-law, the priest of Midian; and he led the flock to the west side of the wilderness and came to Horeb, the mountain of God.
KJV: And Moses went and returned to Jethro his father in law, and said unto him, Let me go, I pray thee, and return unto my brethren which are in Egypt, and see whether they be yet alive. And Jethro said to Moses, Go in peace.
NASB: Then Moses departed and returned to Jethro his father-in-law and said to him, "Please, let me go, that I may return to my brethren who are in Egypt, and see if they are still alive." And Jethro said to Moses, "Go in peace."