Plural of “day”

The plural of day is days.

Why

"Day" comes from Old English "dæg," part of an ancient Germanic word family also found in German "Tag" and Dutch "dag," all tracing back to a shared prehistoric Germanic root for the period of daylight. Because the vowel a sits immediately before the final y, the plural simply adds -s, with the spelling otherwise untouched.

"Day" is a piece of the language's bedrock vocabulary — a word a speaker reaches for countless times before lunch — and words that central almost never sprout competing plural forms the way rarer, later-borrowed nouns in this collection do; its rock-steady "days" reflects both its deep native Germanic roots and how relentlessly it is used. The Germanic root itself is unrelated to the Latin-derived "diurnal" and "journal" (from "dies," day), even though both families of words describe the same basic unit of time, a coincidence of parallel but entirely separate ancient roots rather than any shared linguistic ancestry.

Usage note

"Days" is standard in every context and appears in dozens of fixed phrases, including "these days," "in the old days," and "day by day," all relying on the same simple plural. Measurement uses follow the same adjectival-singular rule seen with "foot": "a three-day trip," not "a three-days trip," while the standalone form still pluralizes normally ("the trip took three days").

"Day" is unusual for how thoroughly it's woven into the grammar of everyday time expressions well beyond simple counting: "weekdays," "weekends," "birthdays," and "holidays" are all compounds built directly on the plural, each treating "day" as a productive building block for naming entire categories of time rather than just counting individual units. Days of the week themselves ("Mondays," "Tuesdays") pluralize with a simple -s when used generally ("she works Mondays"), a distinct grammatical pattern from the noun "day" itself but built on the exact same underlying vowel-plus-y spelling rule.

Common real mistakes

The plural itself carries almost no error risk — the vowel-plus-y rule applies cleanly, and "day" is common enough that even early childhood spelling rarely trips over it. Where writers do genuinely slip is the compound-modifier case: writing "a three-days notice" where "a three-day notice" is called for, the identical trap that catches "foot" and other measurement words pressed into service before another noun. A milder stylistic point rather than a true error: piling up "nowadays" and "these days" in the same paragraph reads as repetitive to careful editors, even though neither phrase is wrong taken on its own.

The wider pattern

"Day" belongs to the vowel-plus-y group alongside "key" and "boy," and as one of the oldest surviving native English nouns still in constant daily use, it stands in useful contrast to the many borrowed, technical, or recently coined words elsewhere on this site.

Examples

• She counted the days until her vacation began.
• Several days passed before the package finally arrived.
• The forecast calls for sunny days through the weekend.
• He worked seven days straight without a break.
• Those were simpler days, according to her grandmother.
• The festival runs for three days each summer.
• Snow days were rare in that part of the country.
• The company observes ten paid holidays and vacation days each year.
• Long summer days made the evenings feel endless.
• The trial lasted nearly thirty days before a verdict was reached.
• The contract requires thirty days notice before cancellation.
• The exhibit runs for only a handful of days before closing.
• She marked the important days on the calendar in red.
• The recipe says to let the dough rest for two full days.
• He counted backward from thirty days until the deadline arrived.
• The forecast predicted rain for the next several days.
• The itinerary listed activities planned for each of the five days.
• The children marked off the remaining days on a paper chain.
• The retreat spanned three quiet days in the mountains.
• The trip lasted only a few short days.