We found 32 dictionaries that define the word porthole:

General (26 matching dictionaries)

1. porthole: Longman Dictionary of Contemporary English
2. porthole: Merriam-Webster
3. porthole: Oxford Learner's Dictionaries
4. porthole: American Heritage Dictionary of the English Language
5. porthole: Collins English Dictionary
6. porthole: Vocabulary.com
7. Porthole, porthole: Wordnik
8. porthole: Cambridge Advanced Learner's Dictionary
9. Porthole, Porthole: InfoVisual Visual Dictionary
10. porthole: Wiktionary
11. porthole: Webster's New World College Dictionary, 4th Ed.
12. porthole: The Wordsmyth English Dictionary-Thesaurus
13. porthole: Infoplease Dictionary
14. Porthole, porthole: Dictionary.com
15. porthole: Online Etymology Dictionary
16. porthole: Cambridge Essential American English Dictionary
17. Porthole: Wikipedia, the Free Encyclopedia
18. Porthole: Online Plain Text English Dictionary
19. porthole: Webster's Revised Unabridged, 1913 Edition
20. porthole: Rhymezone
21. porthole: AllWords.com Multi-Lingual Dictionary
22. porthole: FreeDictionary.org
23. porthole: Mnemonic Dictionary
24. porthole: TheFreeDictionary.com

Business (1 matching dictionary)

25. Travel Industry Dictionary (No longer online)

Computing (1 matching dictionary)

26. porthole: Encyclopedia

Slang (2 matching dictionaries)

27. porthole: Green’s Dictionary of Slang
28. porthole: Urban Dictionary

Tech (2 matching dictionaries)

29. AUTOMOTIVE TERMS (No longer online)
30. SeaTalk Dictionary of English Nautical Language (No longer online)

(Note: See portholes as well.)

Definitions from Wiktionary ( ) ▸ noun:  (archaic) A gunport; an opening in the hull of a ship through which cannon are fired. ▸ noun:  (nautical) A circular window set in the hull of a ship. Similar: port, embrasure, portlight, gunport, portage, portsill, chase port, chaseport, half-port, shot prop, more... Opposite: window Phrases: porthole die, more... Adjectives: open, small, round, tiny, little, single, large, nearest, forward, starboard, closed ▸ Word origin ▸ Words similar to porthole ▸ Usage examples for porthole ▸ Idioms related to porthole ▸ Wikipedia articles (New!) ▸ Popular adjectives describing porthole ▸ Words that often appear near porthole ▸ Rhymes of porthole ▸ Invented words related to porthole