handshake
noun [ C ]
uk/ˈhændʃeɪk/ usa greeting in which two people who are facing each other take hold of each other's right hand and move it up and down:
His charm begins with a warm smile, his arm on your shoulder and a firm handshake.
a business agreement made informally without signing an agreement:
a handshake agreement/deal
On a handshake, I've promised the first car to one of our established customers.
golden handshake
IT
a signal sent from one computer to another to show that they are ready to send and receive information:
Hackers false requests for an electronic handshake with our machines are so numerous that the legitimate requests can't get through.