Wiktionary
n. A haircut where the hair is cut short on the sides and back and allowed to grow long on the top, as though only the hair not covered by an inverted bowl had been removed.
Wikipedia
A bowl cut, or bowl haircut, is a simple and plain short haircut where the hair is cut with a straight fringe on the front and the rest of the hair is the same length all the way around or is cut short on the sides and back. It is so named because it looks as though someone put a bowl on the head and cut off or trimmed short all the visible hair. A bowl cut is also known for being a cheap and easy haircut often sported by children.
Usage examples of "bowl cut".
A line of cliffs vanished into the distance on either side, and immediately opposite him there was a huge double bowl cut out of the cliffs, so that the drop from the bottom of the bowl to the sea was only thirty metres or so.
They came to the rim of a shallow bowl cut into the stone so unexpectedly that he almost tripped and fell, stopping himself on the brim, teetering there for one breath, then stepping back.
Only a scar running across his forehead and up into the bowl cut raven hair marred it.