What does thousandth mean?
The word thousandth denotes the 1000th member or position in an ordered sequence, as in the thousandth day or the thousandth time. It can also denote one of 1000 equal parts of a whole: a thousandth equals 0.001, or one part per thousand. As an adjective, it commonly precedes a noun such as day, time, place, or attempt; as a noun, it follows an article or determiner, as in the thousandth. The word combines the cardinal number thousand with the ordinal suffix -th, following the same pattern as tenth and hundredth. Although its mathematical sense involves a very small quantity, its ordinal sense marks a major milestone, which gives it a potentially memorable and occasionally emphatic use. It is standard in both British and American English and is neither formal nor informal.
The ordinal number denoting the 1000th position in a sequence; also one of 1000 equal parts of a whole.
"The company celebrated the thousandth customer with a full refund."
Plural thousandths is used mainly for the fractional sense, as in three thousandths.
Denoting the 1000th member or position in a sequence.
"On the thousandth attempt, the device finally worked."
The adjective normally appears immediately before the noun it modifies.
Used chiefly when referring to fractional parts, as in two thousandths; ordinal contexts generally take the singular form.
"The solution contained five thousandths of a milligram."
A thousandth is a tiny fraction, but it occupies the memorable milestone of the 1000th place.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does thousandth come from?
Thousandth was formed from thousand and the ordinal suffix -th, on the model of ordinal forms such as tenth and hundredth. Its spelling and pronunciation have remained stable within modern English, while the base word thousand descends from Old English þūsend.
How thousandth is actually used
The word is neutral in register and is used in both everyday and technical contexts. When referring to a fractional part, the form a thousandth or one-thousandth is typical.
Easily confused with thousandth
A thousand is the number 1000, whereas a thousandth is the 1000th item in a sequence or one of 1000 equal parts.