What is the past form of late?

The word "late" doesn't have a past tense form. It's an adjective, meaning "occurring or done after the expected or usual time," or an adverb, meaning "after the usual or expected time."

If you are looking for a past tense word related to "late," you might be thinking of:

* Lately: meaning "recently."

* Late in the context of "He was late" - This is the past tense of "to be" (was) used with the adjective "late."

Let me know if you have a different context in mind and I can help further!