What does duplicate mean?
Duplicate functions as a noun, verb, and adjective, all revolving around the idea of exact repetition. As a noun, a duplicate is an additional copy of something that is identical to the original, such as a spare house key or a second copy of a legal document. As a verb, to duplicate means to produce such a copy, whether physically — photocopying a page — or digitally, as when software detects duplicated files. As an adjective, it describes something that is an exact copy or occurs twice, as in 'a duplicate entry'. The word derives from the Latin 'duplus', meaning twofold, which also gives us 'duplex'. It is neutral in register and widely used in office, legal, computing, and everyday contexts. A notable feature is its shift in stress between parts of speech: DUPLICATE for the noun and adjective, but dupliCATE for the verb. Related phrases like 'in duplicate', meaning producing two identical copies simultaneously, remain standard in administrative English.
An exact copy of something, made in addition to the original.
"She ordered a duplicate of the photograph so each sister could keep one."
In administrative language, 'in duplicate' means producing two identical copies at the same time.
To make an exact copy of something, or to repeat something identically.
"You can duplicate the slide by right-clicking and selecting 'Duplicate Slide'."
Stress shifts to the second syllable when used as a verb: dupliCATE.
Identical to something else; being an exact copy or occurring in pairs.
"The system rejected the form because it contained a duplicate entry."
Standard plural formation; used to refer to multiple copies or instances of duplicated items.
"All duplicates were removed from the database to free up storage space."
The word 'duplicate' literally means 'twofold' — from Latin 'duplus', the same root that gives us 'duplex' — so every duplicate is, etymologically speaking, a doubling.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of duplicate
Duplicate comes from the Latin 'duplicatus', the past participle of 'duplicare', meaning to double, itself derived from 'duplus' — 'twofold' — formed from 'duo' (two) plus the suffix '-plus'. The word entered English in the early 15th century, initially used in legal contexts before broadening to general use. It shares this root with 'duplex', 'duplexity', and ultimately 'double' through related Latin forms, all conveying the sense of two or doubling.
Related word forms
How duplicate is actually used
As a verb, 'duplicate' carries stress on the second syllable (/ˈdjuːplɪkeɪt/), while as a noun and adjective it is stressed on the first syllable (/ˈdjuːplɪkət/) — a distinction shared by words like 'record' and 'present'. In formal or administrative contexts, 'in duplicate' means producing two identical copies at once. The word is neutral in tone and common in both everyday and technical usage, including computing, where it refers to repeated data entries.
Easily confused with duplicate
Replicate means to reproduce something, often in a scientific context and sometimes with variation, whereas duplicate means to make an exact identical copy.
Duplicitous describes someone who is deceitful or two-faced, deriving from the same Latin root but having nothing to do with copying.