Plural of “moth”

The plural of moth is moths.

Why

"Moth" traces back to Old English "moððe" (also spelled "moppe" in some dialects), from a Proto-Germanic root shared with other Germanic languages' words for the insect. Unlike the sibilant-ending words elsewhere on this list, "moth" ends in the consonant cluster "th," which is not a sibilant sound in English — the rule requiring -es (for -s, -ss, -x, -z, -ch, -sh endings) simply doesn't apply here, so "moth" takes the plain, regular -s ending: "moths."

This makes "moth" a genuinely useful contrast case: it looks visually similar to sibilant-ending words like "wish" or "brush" and sits right next to them in casual discussion of "tricky plurals," but it isn't actually irregular at all — the plural is entirely predictable once you know that "th" doesn't trigger the same spelling rule that "sh," "ch," "s," "x," and "z" do.

Usage note

Pronunciation adds a real wrinkle even though spelling doesn't: the final "th" sound shifts from voiceless in the singular ("moth," rhyming with "cloth") to voiced in many speakers' plural pronunciation ("moths," with the "th" sounding closer to "the"), a subtle sound change that happens without any change in spelling — the same shift affects "bath/baths," "path/paths," and "mouth/mouths."

Because this voicing shift is subtle and varies somewhat by regional accent, it rarely causes spelling confusion, but it's part of why some writers instinctively feel "moths" ought to be spelled differently even though it never should be — the ear detects a change the eye doesn't need to track. Moths and butterflies both belong to the order Lepidoptera, and the popular distinction between them (moths fly at night, rest with wings flat; butterflies fly by day, rest with wings upright) is a rough folk classification rather than a strict scientific one, but regardless of which specific insect is meant, the plural stays the same simple, regular "moths."

Common real mistakes

The genuine, if rare, error to watch for is writers mistakenly adding -es by false analogy with visually similar sibilant words, producing "mothes" — this is incorrect; "moth" always takes the plain -s, since "th" was never one of the sounds requiring the extra syllable.

The wider pattern

"Moth" is the odd one out among the sibilant-family words gathered here, precisely because it demonstrates the boundary of that rule: only true sibilant endings (-s, -ss, -sh, -ch, -x, -z) require -es, and consonant clusters that merely sound similar, like "-th," don't, no matter how similar the words look on the page. Some moth species have evolved remarkable camouflage and mimicry, including wing patterns resembling owl eyes to startle predators, a level of specialization that has made certain moths a favorite subject for evolutionary biologists studying predator-prey adaptation, entirely separate from the word's straightforward, unremarkable plural.

Examples

• Dozens of moths gathered around the porch light that summer night.
• The collector had pinned moths from six different countries in his display case.
• Two moths slipped through the screen door before anyone noticed.
• Researchers are tracking how moths respond to increased light pollution.
• The garden attracted moths as well as butterflies once the flowers bloomed.
• Several moths had damaged the wool sweaters stored in the attic.
• The nature documentary filmed moths navigating by moonlight.
• She identified over a dozen species of moths in her backyard alone.
• Moths outnumber butterflies by a wide margin worldwide, though they're rarely noticed.
• The exhibit compared the wing patterns of moths across different climates.
• The porch light drew moths from across the yard every evening.
• Scientists are studying how moths use scent to find mates over long distances.
• The exhibit compared moths and butterflies collected from the same region.
• Two large moths had settled on the window screen by morning.
• The garden moths seemed especially active during the humid August nights.
• Entomologists described three new moths previously unknown to science.
• The exhibit explained how moths use pheromones to find mates across long distances.
• Local moths have adapted their coloring to match the region's tree bark.