Ok, we have learned that the act of zig zagging to get to a destination is called tacking

Now, If the wind is coming from the port (left) side of the boat, then you are on a “port tack”
If the wind is coming from the starboard (right) side of the boat then you are on a “starboard tack”

Turning the boat (tacking) upwind so that the eye of the wind passes from one side of the boat to the other, is called “coming about” or to “come about”

Turning the boat downwind, (also tacking) so that the wind passes from one side of the boat to the other is called Gybing or to gybe. (pronounced JIBE. not to be confused with jib which is a kind of sail)

To “come about” is to tack upwind
To “gybe” is to tack downwind

It is important that the crew is aware if the boat is about to tack, since whether coming about or gybing, the sail will be swinging across the deck. The sail is attached to the mast, and usually to a boom, which is a horizontal tube, or spar, that can whack you in the head if you aren’t paying attention.

coming about
gybing
mast
boom
port tack
starboard tack

In a sentence: We were cooking along on a port tack when the boat gybed accidentally, shaking the mast and scaring the beejezus out of us.

PS port and starboard: here is how you remember which is which. Port wine comes from Portugal. Traditionally, when at the dinner table, you always pass it to the left, if you have any class. We never drank wine at the table, but we did pass the bottle over the carseat at the drive in. Anyway, port = left, then you can figure out the starboard part from there.