We give you definitions , examples , notes on usage , and sometimes we even use them in a conversation . Because it is close to that day that celebrates lovers , we talk today about a romantic idiom : tie the knot . To tie the knot is an informal term for getting married . In some marriage ceremonies , a knot is actually tied around the couple's hands with a piece of cloth or ribbon . This is done as a symbol of unity . This wedding tradition can be called a handfasting ceremony . Several websites claim that this is an ancient Celtic wedding tradition . The couple holds hands while someone else ties their hands together with material . This represents the two people being physically and spiritually tied to each other . But let's go back to the word “knot .” A knot is an interlacing of string , ribbon , rope , or similar material that forms a connection between two , or more , loose ends . The word “knot ” can also describe a mass or lump of disordered material that is tangled . Some knots are hard to untangle . For example , if your hair has knots , the ends have become tangled together , and it cannot be straightened or combed . When talking about hair , having knots is not a good thing . Knowing how to tie knots is important in many activities including sailing . For example , rope is used to secure sails . With a marriage , you want to stay knotted together . You do not want the bond to be easily broken . There are other ways to say to tie the knot . In a formal situation , you can say two people have been wed . A very informal expression is to get hitched . Now , let's hear two friends use the expression “to tie the knot .” Hey , I have a wonderful secret about our good friends Finn and Polly . They are tying the knot next month ! Finn and Polly ? Are you sure ? Polly told me last week while we were bowling . She's on my bowling team . I cannot believe that . Well , believe it . But she made me promise not to say a word . So , don't tell anyone . I am shocked . Finn and Polly have been dating for years . I'm not shocked about that . I had no idea .