A flow of water over the edge of a cliff.
A waterfall-like outpouring of liquid, smoke, etc.
A waterfall of mist came from the open freezer.
Waterfall model
The action of drinking from a vessel without touching it with the lips, considered more sanitary for a shared vessel.
Hey man, can I take a waterfall from your bottle?
A necktie.
A chignon.
A beard.
I found home a dreary place after my long absence; for half the children I had known were now wearing whiskers or waterfalls... (Mark Twain, Roughing It)
To fall like a waterfall.
To drink (something) from a container by pouring it from a height so as not to touch one's lips to the rim.