The foil comes out of the water.
Sometimes you can breach a wingtip and recover and keep going, other times you'll crash.
if it gets close to the surface, it'll suck air in and lose some lift, or will get "aerated". Sometimes you can feel it and correct before you breach completely and then slap the water
I would go with how the term is used for whales, they come completely out of the water, at least 3/4ths of their body does with tail usually staying in the water. So for foils, front wing comes completely out of the water, stabilizer can also come out if you are really powered up!
Select to expand quoteoscardog said..
If you nail it, it's a jump. If you crash, it's a breach.
