triathlon
"The patient was prescribed a new tri medication to treat their depression."
Initialism of Triple Reuptake Inhibitor.
In plain English: A tri is an event that combines running, cycling, and swimming into one race for athletes to complete.
"The tri was held at the local park to celebrate community spirit."
Initialism of Toxic Release Inventory.
"The factory was fined after failing to submit its annual TRI report on hazardous chemical emissions."
The prefix tri comes from the Proto-Indo-European root *tréyes, which means "three." It is used as a shortened form in many English words that begin with this element.