A dispute is in "litigation" ( or being "litigated") when it is the subject of an ongoing and formal court action or law suit.
In Re Kent, a 1982 British Columbia Supreme Court decision, cited as 139 DLR 3d 318, the Court adopted these words:
"The term litigation encompasses the act of carrying on a legal proceeding. A legal proceeding connotes the resolution by a judicial tribunal of an issue between two parties."
The participants - plaintiff, defendant, applicant, petitioner or respondent - are called litigants for so long as the trial is ongoing.