Whats an “OT” ?
Off-Topic. On this board, something that hasn’t anything to do with whistles, or music in general. But being off-topic is sort of on-topic here anyway.
Sonja
So I have this whistle, and it keeps clogging up on me…oops. I’m being OT, here. 
Don’t let them fool you, it means, “On-Topic”, just not the main one.
Actually, since this board runs about 85% off-topic by volume, maybe we ought to redefine “OT” and use it for “On topic” … 
Actually, it stands for “Old Turkey”, and it comes from the Book of Norman…
And, of course, no matter what the topic, it can be made a whistle topic with enough imagination and manuvering. I mean, some whistles are just meant for calling turkeys, aren’t they?
It’s a standard abbreviation for Old Testament. It refers to the old covenant, and, specifically to the portions of Scripture, written under that covenant.