tie the knot
- (idiomatic, intransitive) To marry, wed, get married.
1869, William Makepeace Thackeray, chapter 3, in Burlesques:
- Rowena sacrificed her inclination to remain single, to her sense of duty; and contracted a second matrimonial engagement. . . . Cardinal Pandulfo tied the knot for them.
- 2002, Scott MacLeod, "Live from Baghdad," Time, 25 Nov.,
- After the 20-year-old mechanic tied the knot with his 18-year-old cousin, the newlyweds headed to Baghdad's Ishtar Hotel.
- Used other than with a figurative or idiomatic meaning: see tie, the, knot.