Cacti vs. cactuses

  • Cacti is the Latin plural of cactus, and some writers use it in English. Cactuses is the English plural. Dictionaries list both, and neither is right or wrong. Also, like many names of plants, the uninflected cactus is sometimes treated as plural.


    The prevalence of the Latin cacti can be attributed to the influence of Latin on biological nomenclature. These Latin plurals are not considered out of place in botany and other scientific fields, and some make their way into broader usage, but there’s no good reason that the ordinary English speaker should have to abide by the rules of Latin grammar.

    Cactus is not the only Latin-derived English word ending in –us, and most are conventionally pluralized in the English manner. Fungus, like cactus, often becomes fungi (though funguses is just as good), but this is one of the few exceptions. Most English speakers don’t say ani instead of anuses, apparati instead of apparatuses, campi instead of campuses, octopi instead of octopuses, stati instead of statuses, or viri instead viruses, and there’s no reason cactus should be any didfferent. It’s a matter of preference, though, and cacti is not wrong.



    Though cacti has the edge, both forms are common in current news publications and blogs from throughout the English-speaking world—for example:

    For days, he trekked through desert plains dotted with cacti as vultures circled above his head. [Newsday]

    Text-book cactuses flank the picturesque 449-yard, par-four 14th. [BBC]

    Ringed by cacti and red rock buttes and canyons, the town looks like it once was the set of every shoot ’em up cowboy movie. [National Post]

    But near the visitor center, which was dug into the earth, irrigated areas coaxed succulent blooms from cactuses. [Minneapolis Star Tribune]

    One room has been converted into a type of conservatory, with tiny monkeys swinging from plants, cacti growing out of an old ball-and-claw couch and succulents everywhere. [Mail and Guardian]

    All cacti are succulents, but many other plant families include succulent species. [Monterey County Herald]


    1. Allan Orr says:

      Actually I had several science teachers use apparati, and I’ve always used virii (much to the annoyance of many around me), & cacti myself. Actually most people I know personally who deal with cacti get offended when anyone says cactuses, and around here there’s a lot of people with at least one cactus in their garden.
      English is becoming rather permissive these days to the cult of popularity.

      • Grammarist says:

        The popularity of “cactuses” is by no means new, though, and actually it used to be much more common relative to “cacti” than it is now, as you can see in this ngram:

      • Dain Q. Gore says:

        Yeah, that’s pretty much how language works…the popularity of words is important. “Modern” English has always been permissive that way…we get most of our words from other places, as most growing languages do (in order to grow)…etymology, for example, is a Latin (well, Greek originally) word, as are all of the word plurals you mentioned, which was mentioned in the article.

    2. As this was explained to me, “cacti” refers to many of the same type of plant. And “cactuses” refers to several different types.

    3. Elana Pritchard says:

      There’s a typo in this article, grammarist.

    4. but i’m not sure what to use. some of my teachers say to write ‘cacti’. i’m Australian, so what do they say?

    5. Robert Tichy says:

      Really?! And most college graduates don’t belong to the alumni society of their college or university. They belong to the alumnuses society. Being uneducated is not exactly a sound basis for deciding one is correct.

      • Dain Q. Gore says:

        From the article:

        “Most English speakers don’t say ani instead of anuses, apparati instead of apparatuses, campi instead of campuses, octopi instead of octopuses, stati instead of statuses, or viri instead viruses, and there’s no reason cactus should be any different. It’s a matter of preference, though, and cacti is not wrong.”

    6. Dain Q. Gore says:

      As much as people love to “correct” on the internet, language is not math. There are arbitrary rules we may place on it, but the standard is only as consistent as what people use and mutually understand at any given time (hence the existence of colloquialisms, dialects and neologisms).

      • Meredith Smith says:

        Hence the practice of law… Interpretation. Good point. I have always said cacti myself, although recently it came to my attention that both are acceptable. I do enjoy what a poster said about about how the form changes based on specificity of quantity and kind.

    7. Kelli Kallenborn says:

      The article says the cactus is Latin but actually it is Greek. The -us to -i is for Latin words, not for Greek.

    8. what about Jesus and Jesi :)

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