hook up

informal
to meet or begin to work with another person or other people:
He hooked up with the other members of the band in Amsterdam.

informal
to begin a romantic or sexual relationship with someone:
When did you two first hook up?

a meeting for sex:
Her mother had no idea she was arranging hook-ups with boys in the middle of the night.

a connection to an electricity supply, a telephone network, the internet, etc. :
The campsite has water and electric hook-ups.
He entered his plea from the jail via a video hook-up.
(Cambridge Advanced Learner's Dictionary & Thesaurus からの hook up の定義 © Cambridge University Press)

アメリカ英語辞典
to meet with someone, or to begin a relationship, esp. for a particular purpose:
Give me a call if you'd like to hook up for lunch sometime.
The program is really an opportunity for college kids to hook up and get to know each other.
(Cambridge Academic Content Dictionary からの hook up の定義 © Cambridge University Press)

- Cambridge Dictionary