(n.) Sheet; surface; all that portion of a surface that is continuous in such a way that it is possible to pass from any one point of the portion to any other point of the portion without leaving the surface. Thus, some hyperboloids have one nappe, and some have two.

Niagara bag barf belch bring up burst cataract chute collapse come down comedown crash daggle dangle debacle debouchment declension declination defluxion deluge depend descend descending descension descent dip down disgorge dissiliency down downbend downcome downcurve downfall downflow downgrade downpour downrush downtrend downturn downward trend drabble drag draggle drape droop drop drop down drop off dropping engulf eructation eruption fall fall down fall off falling falls flap flare-up flood flop flow force go down go downhill gravitate gravitation gush hang hang down heave inclination inundate jet linn lop lose altitude nappe nod outbreak outburst overbrim overflow overrun overwhelm parachute pend pitch plummet plummeting plunge pounce pour down pour out pour over precipitate puke rain rapids run over rush sag sault slop slosh spate spew spill spill out spill over spout spurt stoop submerge swag swamp sweep swing swoop throw up torrent trail trend downward upchuck volcan waterfall watershoot weep whelm