We found 24 dictionaries that define the word floodplain:

General (12 matching dictionaries)

1. floodplain: Merriam-Webster
2. floodplain: Oxford Learner's Dictionaries
3. floodplain: American Heritage Dictionary of the English Language
4. floodplain: Vocabulary.com
5. Floodplain, floodplain: Wordnik
6. floodplain: Wiktionary
7. floodplain: Dictionary.com
8. Floodplain (Kronos Quartet album), Floodplain (Sara Groves album), Floodplain: Wikipedia, the Free Encyclopedia
9. floodplain: Rhymezone
10. floodplain: FreeDictionary.org
11. floodplain: Mnemonic Dictionary
12. floodplain: TheFreeDictionary.com

Business (3 matching dictionaries)

13. Travel Industry Dictionary (No longer online)
14. Construction Term Glossary (No longer online)
15. floodplain: Financial dictionary

Computing (1 matching dictionary)

16. floodplain: Encyclopedia

Medicine (1 matching dictionary)

17. online medical dictionary (No longer online)

Science (5 matching dictionaries)

18. Archaeology Wordsmith (No longer online)
19. Field Trip to Mars (No longer online)
20. Botanical Terms (No longer online)
21. Illustrated Glossary of Geologic Terms (No longer online)
22. floodplain: Natural History Terms

Tech (2 matching dictionaries)

23. floodplain: Canadian Soil Information System
24. Glossary of Water Resource Terms (No longer online)

(Note: See floodplains as well.)

Definitions from Wiktionary (floodplain) ▸ noun:  (geography) An alluvial plain adjacent to a river formed by flooding during periods of high rain. Similar: floodland, floodwater, floodflow, floodpool, fluvent, flode, floud, floodtime, fluvaquent, floodlet, more... Types: alluvial, braided, meandering, dendritic, point bar, backwater, overbank, spillway, more... Adjectives: broad, year, wide, lower, alluvial, modern, active, present, narrow, adjacent, flat Colors:     muddy brown,     olive green,     slate gray,     river blue,     marsh green, more... ▸ Words similar to floodplain ▸ Usage examples for floodplain ▸ Idioms related to floodplain ▸ Wikipedia articles (New!) ▸ Popular adjectives describing floodplain ▸ Words that often appear near floodplain ▸ Rhymes of floodplain ▸ Invented words related to floodplain