Speakur

Word Pronunciation & Dictionary

atto-

Word Rarity Very rare

Frequency: Zipf frequency 1.80 in modern English

Syllables
at-to-
IPA
4
Scrabble Score
4
Letters
3
Syllables
3
Unique Chars

Meaning

prefix

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).

Etymology

From Danish atten (“eighteen”), with reference to the (negative) exponent in the relevant power of ten; the same principle also explains femto-.

Origin

Word Breakdown

Frequently Paired Words

mul:a-

Antonyms

exa-

Questions

What does atto- mean?
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).
Where does atto- come from?
It is traced to Danish.

How to pronounce atto-

  1. Open the pronunciation page — Open the Speakur entry for “atto-”.
  2. Read the phonetic spelling — Read the IPA spelling () so you know which sounds to aim for.
  3. Play the audio — Click Play to hear reference audio for “atto-”.
  4. Repeat and practice — Say “atto-” aloud, matching stress and vowels until it feels natural.