simple past tense and past participle of time
"The athletes timed their sprint to start exactly when the gun fired."
In plain English: To timed something means to measure how long it takes for an action to happen.
"We timed our arrival to catch the train just before it left."
Happening at a certain time.
"The fireworks display was timed to explode just as the moon rose above the horizon."
In plain English: Timed means something that happens within a specific amount of time or is measured by how long it takes to finish.
"The timed exam lasted exactly fifty minutes before stopping automatically."