A few days ago, I went by my favorite frame supply store to pick up some acid-free foam core for matting artwork. I had several paintings on full size watercolor sheets to shrink-wrap and could not remember what the dimensions were, so I used my phone to Google it. I ended up on the Wikipedia page about watercolor painting. Granted, the last instruction I received in watercolor was from Mrs. Markle in 1990 or so, but I learned several things.....
I found out that techniques that I incorporate have names! One of my favorite colors to use is cerulean blue because of the "granulation." This is where you can see the pigment particles. I also learned that the effects of ultramarines is called "flocculation."
The capillary action of watercolor when I paint "wet in wet" is the reason that I love it. I never tire of watching the paint move into wet areas and "bloom" (also called backruns, blossoms or oozies); I enjoy adding additional water or wicking paint off the paper back into the brush to manipulate where the color goes. It was fun learning some new terms for what I've been doing for years!
Oh, and a standard full sheet is 22"X 30".