Portuguese man-of-war

noun

plural Portuguese man-of-wars also Portuguese men-of-war
: any of a genus (Physalia of the family Physaliidae) of large, tropical and subtropical, pelagic, siphonophore hydrozoans having a crested bladderlike float which bears the colony comprised of three types of zooids on the lower surface with one of the three having nematocyst-equipped tentacles

Illustration of Portuguese man-of-war

Illustration of <span class=syl>portuguese man<span class=sylbreak>-</span>of<span class=sylbreak>-</span>war</span>
  • Portuguese man-of-war

Examples of Portuguese man-of-war in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Box jellyfish, Portuguese man-of-war, lion’s mane and sea nettle are among highly venomous jellyfish species whose stings require immediate medical attention, per UF Health. — Caroline C. Boyle, USA TODAY, 8 July 2024 Blue dragons, known scientifically as Glaucus atlanticus, sail on the surface of the ocean feeding on toxins from the Portuguese man-of-war and other jellyfish-like organisms. — Priscilla Thompson, NBC News, 9 Mar. 2024

Word History

First Known Use

1707, in the meaning defined above

Time Traveler
The first known use of Portuguese man-of-war was in 1707

Rhymes for Portuguese man-of-war

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Portuguese man-of-war
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Cite this Entry

“Portuguese man-of-war.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Portuguese%20man-of-war. Accessed 10 Mar. 2025.

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Kids Definition

Portuguese man-of-war

noun
plural Portuguese man-of-wars also Portuguese men-of-war
: any of several large colonial invertebrate animals that are hydrozoans and float on the surface of the sea by means of a large gas-filled structure like a bag and have long tentacles capable of delivering a painful sting

Medical Definition

Portuguese man-of-war

noun
Por·​tu·​guese man-of-war ˌpȯr-chə-ˌgēz-ˌman-əv-ˈwȯr How to pronounce Portuguese man-of-war (audio)
plural Portuguese man-of-wars -ˈwȯrz How to pronounce Portuguese man-of-war (audio) also Portuguese men-of-war -ˌmen-əv-ˈwȯr How to pronounce Portuguese man-of-war (audio)
: any siphonophore of the genus Physalia including large tropical and subtropical oceanic forms having a crested bladderlike float which bears a colony comprised of three types of zooids on the lower surface with one of the three having stinging tentacles

More from Merriam-Webster on Portuguese man-of-war

Britannica.com: Encyclopedia article about Portuguese man-of-war

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