Noun

1. A prearranged meeting or assignation, now especially between lovers to meet at a specific place and time.
   • 2005: Julian Baggini, The Pig that Wants to be Eaten: And 99 other thought experiments, №91: “No one gets hurt”, page 271 (Granta; ISBN 1862078556, 9781862078550)

     If someone trusts you, what is lost if you betray that trust? As Scarlett is tempted to see it, sometimes nothing at all. If her husband remains ignorant of her tryst, then his trust in her will remain intact. ‘No one gets hurt’ runs her reasoning, so why not go ahead?

2. A mutual agreement, a covenant.

Verb

1. To make a tryst; to agree to meet at a place.
2. To arrange or appoint (a meeting time etc.).
3. To keep a tryst, to meet at an agreed place and time.