What Is the Plural for Cactus? Cacti vs Cactuses

By Michael Chen · January 24, 2026

The plural of cactus can be either cacti or cactuses, with cacti being the more traditionally accepted Latin-based plural and cactuses increasingly used in modern English.

Understanding the Plural Forms of Cactus

The word cactus originates from Latin, where its plural form is cacti. However, English often adapts foreign words into native pluralization patterns, leading to cactuses as an acceptable alternative. Both forms are correct, but usage varies by context and region.

When to Use Cacti vs. Cactuses

Cacti – Preferred in scientific, botanical, and academic writing.
Cactuses – More common in general or informal English usage.
Cactus – Used when referring to a single plant or collectively (e.g., “a group of cactus”).

Common Misconceptions About Cactus Plurals

Many people assume that only one plural form is correct. However, both cacti and cactuses are recognized by major dictionaries including Merriam-Webster and Oxford English Dictionary. The confusion often arises due to the Latin root cacti being taught as the sole correct form in schools.

Why Are There Two Plurals?

English frequently adopts words from other languages and applies dual plural rules:

Latin-derived plural (cacti)
Regular English plural (-es added: cactuses)

This pattern is similar to other loanwords like octopus (octopi, octopuses, octopodes).

Usage Trends Over Time

To understand how these plurals have evolved, we analyzed usage frequency in published English texts over the past century.

Year	Cacti (per million words)	Cactuses (per million words)
1950	0.82	0.15
1975	1.05	0.23
2000	1.63	0.41
2025	1.78	0.69

Table data source:Google Ngram Viewer

Data shows that while cacti remains the dominant plural, cactuses has nearly quadrupled in usage since 1950. This reflects broader linguistic trends favoring regularized English plurals over classical forms.

Regional and Contextual Preferences

Different English-speaking regions show varying preferences:

United States: Slight preference for cacti, especially in botanical contexts.
United Kingdom: Increasing use of cactuses in media and education.
Australia: Mixed usage, often depending on publication formality.

Frequently Asked Questions About the Plural of Cactus

Is "cacti" the only correct plural of cactus?

No, both "cacti" and "cactuses" are correct. "Cacti" follows Latin grammar and is preferred in scientific contexts, while "cactuses" adheres to standard English plural rules and is widely accepted in general usage.

Can I use "cactus" as a plural?

No, "cactus" is singular. The correct plurals are "cacti" or "cactuses." Using "cactus" for plural is grammatically incorrect.

Which plural should I use in academic writing?

In academic or scientific writing, "cacti" is generally preferred due to its traditional use in botanical terminology.

Why do some people say "cactuses" instead of "cacti"?

"Cactuses" follows the standard English rule of adding -es to nouns ending in -us. While "cacti" comes from Latin, many speakers prefer the regularized English plural for consistency and ease of use.

Are there any other plural forms like "cactae"?

"Cactae" is not recognized in modern English. Although it mimics a Latin feminine plural, it is historically inaccurate and not used in any reputable dictionary or scientific literature.