What is the plural possessive of cactus - cactuses' or cacti's?

Answer 1

Either is correct: cactuses' or cacti's.

The apostrophe only is used when a plural is formed by S or ES, to indicate that an additional S sound is not added. When a plural does not end in S, the ordinary possessive (apostrophe-S) is used.

Both cactuses and cacti are acceptable plurals for cactus.

Answer 2

The plural forms for cactus are cacti or cactuses, both are accepted.

Some words that come from Latin, such as cactus, stimulus, nucleus, and radius, still act as they did in Latin. That is, they form a plural by replacing the -us with -i. For some words (such as radius) the ordinary English rules of plurals are often used. Many words that end in -us (such as octopus) are not from Latin, but the -i plural is mistakenly applied.

Singular ends in -us/Plural ends in -i:

• alumnus/ alumni
• bacillus/ bacilli
• cactus/ cacti
• nucleus/ nuclei
• stimulus/ stimuli
• focus/ foci
• radius/ radii
• terminus/ termini
• villus/ villi

Of course to confuse the issue further, the English plural of "virus" is "viruses" not viri; and the word platypus forms the plurals platypus or platypuses, not platypi.

Answer 3

The plural form without an 's' is cacti.

Another accepted plural for cactus is cactuses.

Answer 4

The plural of cactus is cacti. The regular form of cactuses is also acceptable.

Answer 5

Cacti is the plural of cactus.

Answer 6

You aren’t __________ brighter than him.