A soggy taxonomy

WARNING: MAJOR GEEK-FEST AHEAD!

The wind has really been roaring around Cambridge the last two days, which reminds me of a conversation I had recently, trying to figure out the difference between a bog, marsh, fen, moor, etc.  Think about it: can you really tell me the distinguishing features?  So here goes, courtesy of the OED:

Fen
1a. Low land covered wholly or partially with shallow water, or subject to frequent inundations; a tract of such land, a marsh.
b. esp. the fen (obs.), the fens: certain low-lying districts in Cambridgeshire, Lincolnshire, and some adjoining counties.


Cambridge, I've heard repeatedly, is in a fen.  People usually say this by way of vaguely complaining/making fun of it for being flat land with less-than-perfect weather.  Arthur Hallam, Tennyson's best friend, referred to it as "this college-studded marsh."  Which brings us to...

Marsh
Low-lying land, often flooded in wet weather and usually more or less waterlogged throughout the year; a tract or area of such land.

So, much the same thing but more consistently water-filled "throughout the year."

Moor
1. Originally: a marsh; marshland, fen (obs.). Now: any of the flat, low-lying areas of Somerset, England, which were formerly marshland.
2. A piece of unenclosed waste ground; (now usually, esp. in Brit.) uncultivated ground covered with heather; a heath. Also: a tract of ground strictly preserved for shooting.

The first one suggests that all these terms used to be basically interchangeable.  Based on my many readings of the classic children's book The Secret Garden, I'm going to go with definition #2, uncultivated & covered with heather.

Bog
A piece of wet spongy ground, consisting chiefly of decayed or decaying moss and other vegetable matter, too soft to bear the weight of any heavy body upon its surface; a morass or moss.


At last, a distinct definition!


Morass
A wet swampy tract, a bog, a marsh; an area of very wet or muddy ground; (as a mass noun) boggy land.
Now we're just repeating ourselves.  But another one that's often metaphorical is...

Mire

An area of swampy ground; a boggy place, esp. one in which a person may be engulfed or become stuck fast.

Interesting how this one is mostly defined by its effect.

Slough

A piece of soft, miry, or muddy ground.

Swamp
A tract of low-lying ground in which water collects; a piece of wet spongy ground; a marsh or bog. Orig. and in early use only in the N. American colonies, where it denoted a tract of rich soil having a growth of trees and other vegetation, but too moist for cultivation


Who knew that swamps are only American?  Speaking of which, here's one the OED labels as only a U.S. word:


Everglade
A marshy tract of land mostly under water and covered in places with tall grass; chiefly in pl. as the name of a large swampy region of South Florida.


The best part of this entry is that they have no idea where the word came from:
Etymology:  ? < ever adv. + glade n.¹
The formation is irregular, and the intended etymological sense uncertain; perhaps ever was used to mean ‘interminable’.



And let's not forget...
Bayou
The name given (chiefly in the southern States of N. America) to the marshy off-shoots and overflowings of lakes and rivers.


Bonus fact: it's from Choctaw (by way of American French).


So it turns out that, except for the decaying-moss specificity of "bog," and the American-only nature of a few, these words have always been more or less interchangeable.  In fact, Beowulf uses them right next to each other:


"Se þe moras heold, fen ond fæsten"
[Something like, "he who holds the moors, in fen and stronghold"]


In short, this waterlogged taxonomy has shown that there isn't much difference at all.  Hurray. =P