marsh Definition

1. A poorly-drained, low-lying, frequently-flooded area of land, commonly found at the mouths of rivers and alongside ponds and lakes. See also fen, swamp.

Thesaurus: swamp, morass, bog, quagmire, bayou.
2. Such an area of land lying in the intertidal zone that is periodically flooded by seawater.

Form: salt marsh (also)

1. Inhabiting or found in marshes.

Example: marsh marigold