atto-

See also: atto, attó, attò, and attõ

English

Etymology

From Danish atten (“eighteen”), extending the idea to how femto- is derived from Danish femten (“fifteen”) and the fermi unit.

Prefix

SI prefix

a	Previous:	zepto-
	Next:	femto-

atto-

1. In the International System of Units and other metric systems of units, multiplying the unit to which it is attached by 10⁻¹⁸ (short scale quintillionth or long scale trillionth). Symbol: a

Antonyms

• exa-

Derived terms

English terms prefixed with atto-

attoampere

attobarn

attocell

attoclock

attogram

attohertz

attojoule

attokatal

attoliter

attolitre

attometer

attometre

attomolar

atto-mole

attomole

attoparsec

attophysics

attopulse

attoreactor

attosecond

attowatt

Translations

unit of measure

• Catalan: atto-
• Chinese:

  Mandarin: 阿托 (zh) (ātuō)

• Danish: atto-
• Dutch: atto- (nl)
• Finnish: atto- (fi)
• French: atto- (fr)
• Galician: atto- (gl)
• Georgian: ატო- (aṭo-)
• Hungarian: atto- (hu)
• Icelandic: attó-
• Indonesian: ato-
• Irish: ata-
• Japanese: アト- (ato-)
• Malay: ato-
• Polish: atto- (pl)
• Russian: атто- (ru) (atto-)
• Thai: อัตโต- (at-too-)
• Ukrainian: атто- (atto-)
• Vietnamese: a-tô

Anagrams

• to a T, toat, tota

Catalan

Etymology

Borrowed from Danish atten (“eighteen”).

Prefix

atto-

1. atto-

Further reading

• “atto-” in Diccionari de la llengua catalana, segona edició, Institut d’Estudis Catalans.
• “atto-”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2025
• “atto-” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.

Danish

Etymology

From atten (“eighteen”).

Prefix

atto-

1. atto-

Dutch

Etymology

From Danish atten (“eighteen”).

Pronunciation

• IPA^(key): /ˈɑ.toː/

• Audio:

  (file)

Prefix

atto-

1. atto-

Dutch terms prefixed with atto-

attocandela

attometer

attoseconde

Finnish

Etymology

Internationalism (see English atto-).

Pronunciation

• IPA^(key): /ˈɑtːo-/, [ˈɑ̝t̪ːo̞-]

Prefix

atto-

1. atto-

Further reading

• “atto-”, in Kielitoimiston sanakirja [Dictionary of Contemporary Finnish]‎^[1] (in Finnish) (online dictionary, continuously updated), Kotimaisten kielten keskuksen verkkojulkaisuja 35, Helsinki: Kotimaisten kielten tutkimuskeskus (Institute for the Languages of Finland), 2004–, retrieved 2023-07-02

Anagrams

• otat, taot, tota

French

Pronunciation

• Audio:

  (file)

Prefix

atto-

1. atto-

Polish

Etymology

Etymology tree

Proto-Indo-European *oḱtṓw

Proto-Germanic *ahtōu

Proto-Indo-European *déḱm̥t

Proto-Germanic *tehun

Proto-Germanic *ahtōutehun

Old Norse áttján

Danish attender.

Polish atto-

Derived from Danish atten.

Pronunciation

• IPA^(key): /at.tɔ/

• Audio:

  (file)

• Rhymes: -attɔ
• Syllabification: [please specify syllabification manually]

Prefix

atto-

1. atto-

   ‎atto- + ‎sekunda → ‎attosekunda

Derived terms

Polish terms prefixed with atto-

attosekunda

Further reading

• atto- in Polish dictionaries at PWN

Spanish

Etymology

Borrowed from Danish atten (“eighteen”).

Pronunciation

• IPA^(key): /ˈadto/ [ˈað̞.t̪o]
• Rhymes: -adto

Prefix

atto-

1. atto-

Further reading

• “atto-”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8, Royal Spanish Academy [Spanish: Real Academia Española], 2024 December 10