flat ground
alluvial plain, coastal plain, delta, delta plain.
Plain, boring
just plain nervousness
fundamental simple plain ordinary
Flood plain, alluvial plain, tidal plain, firth, inlet, bayou, estuary, slough, and river mouth are all terms that are synonymous with 'delta'.
Its swampI think a better synonym is plain (extensive area of flat land). A swamp is a wet damp place, prairies or plain are not necessarily wet.
No, it is a synonym. Antonyms have opposite meanings.
plain (homophone for plane)
CHROMATIC:SYNONYM: colorful,flashy,brightANTONYM:dull,plain,boring
Synonyms for steppe include grassland, plain, prairie, and savanna.
snug, simple, plain
acres, agricultural region, alkali flat, alluvial plain