nanosecond

noun

nano·​sec·​ond ˈna-nə-ˌse-kənd 

-kənt

1

: one billionth of a second

2

: a very brief moment

Did you know?

The nonserious use of nanosecond is probably much more common than the proper technical use. In measurement terms such as nanosecond, nanogram, and nanometer, nano- means "billionth;" in other kinds of words, its meaning isn't quite so precise. In computers, the speed of reading and writing to random access memory (RAM) is measured in nanoseconds. By comparison, the speed of reading or writing to a hard drive or a CD-ROM player, or for information to travel over the Internet, is measured in milliseconds (thousandths of a second), which are a million times longer than nanoseconds.

Synonyms of nanosecond

• minute
• second
• heartbeat
• moment

Examples of nanosecond in a Sentence

It happens in less than a nanosecond.

a nanosecond was about all that it took her to accept his marriage proposal

Recent Examples on the Web

Instead, the past week has been spent relitigating the final nanoseconds of the Wolverines’ 13-12 victory against Western Michigan. — Austin Meek, New York Times, 11 Sep. 2026

Round-trip latency could fall from the microsecond range to several hundred nanoseconds, representing a reduction of up to an order of magnitude. — Neetika Walter, Interesting Engineering, 8 Sep. 2026

Such as approach had its own speed limits – at the slowest, nanoseconds (billionths) and at the fastest, picoseconds (trillionths). — New Atlas, 20 Aug. 2026

Xona expects its satellites to eventually deliver a timing reference accurate to within 10 nanoseconds. — Jeremy Hsu, ArsTechnica, 16 July 2026

Word History

Etymology

International Scientific Vocabulary

First Known Use

1958, in the meaning defined at sense 1

Rhymes for nanosecond

• femtosecond
• microsecond
• millisecond
• picosecond
• beckoned
• reckoned
• second
• seconde

Kids Definition

nanosecond

noun

nano·​sec·​ond ˈnan-ə-ˌsek-ənd 

-ənt

: one billionth of a second

Medical Definition

nanosecond

noun

nano·​sec·​ond -ˌsek-ənd, -ənt 

: one billionth of a second

—abbreviation ns, nsec