noun
summons
SUM-unz/ˈsʌmənz/
An official or direct call to appear, attend, or respond.
The witness receives a summons to appear in court next week.

Etymology
“Under” plus “advise” formed a Latin verb meaning to remind or advise privately. This developed into calling someone to appear, especially by authority—the central idea of a summons.
In context
someone sues you you get a summons and a complaint and you'd have to go to court presumably hire an attorney
More examples
- At the director's summons, the team gathers in her office.
- You must respond to the summons by the stated deadline.
- The clerk mails summonses to potential jurors.
Forms
summons · summonses
summon verb — To call someone to appear or respond.