I told Korean friends not to label a (non-commercial) package of seaweed as "seafood", but it is from the sea and it is food, so now I'm not sure.

How common is it to refer to "seaweed" as "seafood"?

Does this vary from place to place?

  • 9
    It depends entirely on whose definition you use. It's not a precisely-defined term (except perhaps in some government regulations).
    – Hot Licks
    May 18, 2017 at 12:50
  • 4
    It is more common to refer to seaweed as "Sea Vegetables".
    – Chenmunka
    May 18, 2017 at 13:06
  • 4
    @HotLicks are you aware of any seaweed-inclusive definitions?
    – DavePhD
    May 18, 2017 at 15:52
  • 15
    Laver or kombu may be sea food, but that doesn't make them seafood, much as the wild horses that play in the surf at Assateague National Seashore are sea horses, but very far from seahorses.
    – choster
    May 18, 2017 at 18:23
  • 6
    @choster but are the Assateague horses seafood? :)
    – DavePhD
    May 18, 2017 at 18:28

7 Answers 7


I wasn't able to find any dictionary which included plant-based food in the definition of "seafood."

Merriam-Webster (American English):

edible marine fish and shellfish

American Heritage:

Edible fish or shellfish from the sea.

Chambers (British):

Shellfish and other edible marine fish.

Some other sources:

So it seems like seaweed can be considered seafood, but it does not seem to be common practice. I would never use the term to refer to seaweed or other plant-based food.

  • 6
    Seaweed is a seasoning, according to the FDA. As far as I am aware, it's fairly uncommon to refer to seasonings as food in everyday usage.
    – dma1324
    May 18, 2017 at 21:31
  • 4
    I would also note that people often have "seafood allergies," which to the best of my understanding do not include seaweed.
    – Cort Ammon
    May 18, 2017 at 21:47
  • 4
    @dma1324 Some people would also call crumbled bacon a seasoning.
    – Evan
    May 18, 2017 at 21:55
  • 1
    @dma1324 FDA might be working as a reference for American culture, but I strongly suspect, seaweed is seen as more than seasoning in Korea.
    – skymningen
    May 19, 2017 at 10:14
  • 1
    @KevinFegan what really happened was a proposed rule (concerning school lunches) printed in the Federal Register had an example discussed and it was written "could credit a condiment such as pickle relish as a vegetable". Then news media started saying the stuff about ketchup. washingtonpost.com/archive/politics/1982/01/07/…
    – DavePhD
    May 22, 2017 at 17:45

A state of Connecticut definition (for the purpose of a specific law concerning the requirement of a certificate of registration for the retail sale of seafood) is:

"Seafood" means all fresh or saltwater finfish, molluscan shellfish, crustaceans and other forms of aquatic animal life

[emphasis added]

which would lead us to believe that plant products are not included in the category 'seafood'.

  • 8
    Académie Française; Real Academia Española; State of Connecticut ;-)
    – Sneftel
    May 18, 2017 at 15:41
  • 1
    Presumably, this is for labeling laws in the sale of these foods, correct?
    – trlkly
    May 19, 2017 at 0:24
  • 2
    @trlkly the definition in this answer only applies to a particular law in Connecticut, not the rest of the USA. It only applies to the sentence "No person, firm, corporation, limited liability company or other legal entity shall engage in the wholesale distribution of meat or meat food products or in the retail sale of seafood without first obtaining a certificate of registration."
    – DavePhD
    May 19, 2017 at 1:25
  • 1
    I think the caveat/clarification contained in the previous comment is significant enough to warrant editing the answer to include it.
    – John Y
    May 19, 2017 at 22:23
  • @JohnY ok, I added
    – DavePhD
    May 21, 2017 at 14:32

For a product label, it is fine to call it seafood, although a bit strange. We typically use the word seafood as a general category of foods or restaurants. Although basil is a type of plant, we wouldn't call it a vegetable.

  • 2
    Basil is an herb, not a vegetable. Plant-based foods are broken into a number of different categories other than vegetable. The most obvious one is of course fruit, but then there are also herbs, spices, nuts, and grains. None of these terms are interchangeable. Seeds are another category but they sometimes fall under some of the other categories, most commonly spices or grains.
    – O.M.Y.
    May 19, 2017 at 13:38
  • 1
    @O.M.Y. the word "vegetable" has multiple definitions. The broadest one would include basil – think of the "animal, vegetable, mineral" categories in twenty questions. AHD 1c. "A member of the vegetable kingdom, especially a green plant."
    – herisson
    May 20, 2017 at 22:19
  • @sumelic The "vegetable kingdom" (Regnum Vegetabile) is an archaic term from the 18th century. Today we refer to this as the "plant kingdom" (Kingdom Plantae) instead because it includes vegetables, fruits, non-food plants such as timber trees, and even algae. Since this StackExchange is about the English language this is not a trivial point here.
    – O.M.Y.
    May 21, 2017 at 3:00

but it is from the sea and it is food, so now I'm not sure

This is a common misconception. Language categories don't work at all like mathematical sets, but most of us are unaware of it. So people try to treat them as they were working that way, or even start insisting that language is "incorrect" because it doesn't obey the same rules.

In mathematics, sets are defined by their inclusion conditions. If a triangle has two equal sides, it belongs to the set of isosceles triangles, else it doesn't.

In language, category membership is defined by the degree of similarity to a prototypical item, and it is gradual, unlike set membership. The prototypical "bread" in American English is a tin-baked spongy loaf leavened with yeast. A Central European style sourdough boule loaf is still quite universally recognized as "bread" even though it is not the first one that comes to mind to an American. Items like challah or a banana bread are farther apart and some people under some circumstances will say "yes" when asked if they are bread, while other people in other contexts will say "no". But if you ask an American baker if a Liege waffle is bread, I expect the answer to be a resounding "no". At the same time, if you ask American bakers what makes a bread bread, the first criterion that comes to mind will probably be "it is a baked good made with yeast" (and a Liege waffle is made with yeast). So, while the criteria do exist, you cannot apply them the same way as you can apply them to sets. ("If it is baked and made with yeast, it is bread").

So of course you can ask for a definition of a category, but have to be aware that not all items which fit the definition are actual members of the category, and that items which don't fit the definition can act as a member of the category (permanently or under special circumstances).

This explains your confusion. You assumed that "if it is food, and comes from the sea, it must be seafood". Unlike a geometrical figure ("if it is a triangle, and has a right angle, it must be a right triangle") seafood does not care for a boolean match of necessary and sufficient conditions. You have to look at the traditional usage and the prototype items of the category.

This is what your brain did naturally the first time, before you started second-guessing your wisdom. Edible seaweed is certainly not considered seafood by native English speakers, at least within the US and British cultures. I don't know the exact prototype item for the category, but my guess would be that it is some subset (mathematically defined this time) of mussels, scallops, shrimps and fish.

If you are interesting in background reading on membership in linguistic categories, I can highly recommend George Lakoff.


I asked my wife who works in the industry, selling food and supplies to restaurants.

seafood is indeed inclusive of vegetables, specifically sea weed.


Seafood generally applies to crustaceans, fish, cephalopods, and ocean mammals; basically sea animals. Here's a definition from Merriam-Webster that says that: edible marine fish and shellfish. Seaweed would be considered food from the sea, but not necessarily seafood. Seaweeds are plants and algae, so not animals. Marking it as seafood would likely confuse English speakers.


I think this belongs in a different category, given the "classical" definition of seafood belonging to fish, shellfish, etc. May I propose "seagan" or "seagetarian"?

Now, if this is purely a "practical" definition we're seeking here that will get you past customs, go with "vegetable" or "plant material". Warning, though, it might not make it through some Customs inspections due to limitations on what can be transported across borders, regardless of whether you pick a "P.C." name or not.

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    – choster
    May 20, 2017 at 0:31

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