The phrase "year dot" refers to a time so long ago that it is difficult to determine the exact year. It is often used to emphasize that something has been happening since the very beginning or for a very long time.
Sentences with «year dot»
Come on — it has been like that for all fans since year dot. (justarsenal.com)
Seven postseason teams from last year dot the schedule, including five in the first nine matches. (anonymouseagle.com)
Take the time to turn off the highway into the main street and explore the shops many of which have been there since year dot. (coastalstays.com)