How to Use Cactus Plural (Explained, Examples & Worksheet)

“Cacti” or “cactuses”: what’s the plural of cactus?

If you’re in the Arizona desert and spot a cactus …and then another …how would you describe what you saw? Would you say you saw cacti or cactuses or …cactopodes?

Whether you’ve been saying cacti or cactuses, either way you’d be correct. Both spellings are common plurals for cactus (singular noun). Cactus comes from the Greek, κακτος. Its first recorded use is by the Greek botanist Theophrastus, describing a spiny plant.

Cactus comes from the Greek, κακτος. Its first recorded use is by the Greek botanist Theophrastus, describing a spiny plant.

The history of the cactus

Cactus originally came from the Greek word kaktos, which was the name for a type of prickly plant in Sicily. Carl Linnaeus gave the name to these spiked and leafless American plants that we now refer to as cactuses, believing that possibly the cactus was the long distant relative to the classical Sicilian plant. This occurred in 1769, once the word had already entered and evolved from Latin.

That’s the history of the word cactus, and despite being originally Greek, cactus still uses Latin suffixes to denote both singular and plural noun forms. There are still many commonly used Latin noun forms in English that follow the same pattern as cactus.

Think of other words in English like fungus, alumnus and syllabus: they all switch to “i” as a plural, the plural of fungus is fungi, alumnus is alumni and syllabus becomes syllabi. Cacti, likewise, is still accepted and recognized as a plural to mean more than one of these desert succulents.

Cactuses / cacti

Cactuses uses the standard Americanized plural noun form, and adds an -es to show a plural. This spelling is also accepted and widely used in conversation and writing.

What’s the takeaway on the correct plural of cactus? Well, the answer is that there are two correct ways to refer to more than one cactus: cacti and cactuses. One is not technically more correct or better than the other, but if you want to stick to the original Latin form, you can use cacti. The choice is ultimately yours to make, we’re just here as a friendly guide.

Nouns that end in -us

Cactus is an irregular plural noun that does not end in the typical -s/-es that regular plural noun forms take. The plural of cactus is often confused, since its original plural form, cacti, is irregular in English, and fairly uncommon. Still, cactus is not alone: fungus, alumnus, octopus, hippopotamus, all end in -us in their singular noun form. Likewise, each behaves the same in their plural forms, and substitute the -us for -i: fungi, alumni, cacti, octopi (octopuses), and hippopotami (or hippopotamuses).

Aside from being irregular plural noun forms, these words all share a common history, and have Latin origin. Latinate suffixes, or words that derive from Latin rather than, say, Old English or Germanic languages (which is what mostly makes up the English language), still imitate their Latin form.

Words like fungus, alumnus, cactus, and other similar Latin nouns continue to use their original Latin form in the singular and plural.

What are cacti?

Cacti are:

any of a family (Cactaceae, the cactus family) of plants that have succulent stems and branches with scales or spines instead of leaves and are found especially in dry areas (such as deserts).

Cacti/cactuses in application

Origin of the word cactus

c. 1600 from Latin cactus, from Greek kaktos, name of a type of prickly plant of Sicily (the Spanish artichoke), a “foreign word of unknown origin.”

Practice: Latin nouns, Cactus

FAQs

Sources

1. 
   
   Harper Douglas, “Etymology of cactus,” Online Etymology Dictionary, accessed March 8, 2023, https://www.etymonline.com/word/cactus.