Something that’s tricoté serré in the French of Québec is “tight knit” or “close knit.”
Tricoter to means “to knit,” and serré means “tight.”
But like its English equivalent, the expression tricoté serré also has a figurative meaning where it refers to strong bonds between people.
What kinds of things can be tricoté serré?
une communauté tricotée serrée
a tight-knit community
(its residents care about and support one another)
une famille tricotée serrée
a tight-knit family
(the family members are very close to one another)
And in the photo that I took above of a newspaper ad, apparently a couple in a relationship can also be tricoté serré:
un couple tricoté serré
a tight-knit couple
The company in this ad is promoting a special offer on two mobile phones for couples tricotés serrés, who undoubtedly rack up the minutes by giggling together on the phone for hours.
The two lovers in the ad are also wearing the same knitted sweaters, which hints at the literal meaning of the expression tricoté serré.
My two cents, in French: http://oreilletendue.com/2010/11/02/une-maille-a-l%E2%80%99endroit-une-maille-a-l%E2%80%99envers/