We found 25 dictionaries that define the word u-boat:

General (21 matching dictionaries)

1. U-boat, U-boat: Merriam-Webster
2. U-boat: Oxford Learner's Dictionaries
3. U-boat: American Heritage Dictionary of the English Language
4. U-boat, U-boat: Collins English Dictionary
5. U-boat: Vocabulary.com
6. U-Boat, U-boat: Wordnik
7. U-boat, u-boat: Cambridge Advanced Learner's Dictionary
8. U-boat: Wiktionary
9. U-boat: Webster's New World College Dictionary, 4th Ed.
10. U-boat: The Wordsmyth English Dictionary-Thesaurus
11. U-boat: Infoplease Dictionary
12. u-boat: Dictionary.com
13. U-boat: Online Etymology Dictionary
14. U-Boat, U-boat: Wikipedia, the Free Encyclopedia
15. U-boat: Rhymezone
16. U-boat: Stammtisch Beau Fleuve Acronyms
17. u-boat: FreeDictionary.org
18. u-boat: Mnemonic Dictionary
19. U-boat: TheFreeDictionary.com

Computing (1 matching dictionary)

20. U-boat: Encyclopedia

Miscellaneous (1 matching dictionary)

21. U-boat: Acronym Finder

Slang (1 matching dictionary)

22. U-boat: Urban Dictionary

Tech (1 matching dictionary)

23. Sweetwater Music (No longer online)

(Note: See u-boats as well.)

Definitions from WordNet (U-boat) ▸ noun:  a submersible warship usually armed with torpedoes Similar: pigboat, sub, submarine, E-boat, Q-boat, PT boat, hunter-killer, undercraft, gun boat, submersible, more... Opposite: surface ship, destroyer, cruiser, aircraft carrier, battleship Phrases: Uncompleted U-boat projects, U-boat campaign, Atlantic U-boat campaign of World War I, Rocket U-boat, 9th U-boat Flotilla, more... ▸ Word origin ▸ Words similar to u-boat ▸ Usage examples for u-boat ▸ Idioms related to u-boat ▸ Wikipedia articles (New!) ▸ Popular adjectives describing u-boat ▸ Words that often appear near u-boat ▸ Rhymes of u-boat ▸ Invented words related to u-boat