bog - wet spongy ground; especially : a poorly drained usually acid area rich in accumulated plant material, frequentlysurrounding a body of open water, and having a characteristic flora (as of sedges, heaths, and sphagnum (and carnivorous plants!))

swamp - a wetland often partially or intermittently covered with water; especially : one dominated by woody vegetation (like cypress trees and stuff.)

marsh - a tract of soft wet land usually characterized by monocotyledons (as grasses or cattails)

slough - a place of deep mud or mire, a creek in a marsh or tide flat

glade - an open space surrounded by woods.  Not really a wetland, but might surround a fen or bog.

fen - low land covered wholly or partly with water unless artificially drained.  Kind of like a bog, but with higher nutrient levels.  Maybe a bog wannabe?

savannah - a treeless plain especially in Florida, usually seasonally flooded.

moor - a boggy area; especially : one that is peaty and dominated by grasses and sedges

muskeg - a sphagnum bog of northern No. America often with tussocks

pocosin - an upland swamp of the coastal plain of the southeastern U.S.

carr - a chiefly British fen.

vernal pool - a pool of water forming in the spring, usually dry part of the year

pond - an open body of water smaller than a lake

lake - an open body of water larger than a pond

reservoir - an artificial body where water is collected and kept in quantity for use