i.e.

IPA/ˈaɪ ˈiː/
IPA/ˈaɪ ˈiː/

i.e. — abbreviation

1. a written abbreviation from the Latin phrase 'id est', used to introduce a more

1.abbreviationintransitiveB1
Definition

a written abbreviation from the Latin phrase 'id est', used to introduce a more exact or clearer explanation of something that has just been said — for example, saying 'I will meet you next Friday, i.e., the 16th' to remove any doubt about which day is meant.

Example

Our tour guide said to meet at the main entrance, i.e., the glass doors facing the park.

i.e. used between a general place and a specific one

Mayumi borrowed a book on Portuguese history, i.e., a 400-page study of the colonial period.

i.e. introducing a more detailed description of a noun

Synonyms
  • that is

    the full English equivalent of i.e.; used in the same clarifying function

  • namely

    more formal than i.e., often used in academic or legal writing

  • in other words

    slightly longer but interchangeable; works in both writing and speech

Usage Note

Always written with two periods and no spaces between the letters (i.e.), though some style guides place a comma after it (i.e.,). Typically appears in writing rather than spoken conversation.

Common Mistakes

I need to buy fruit, i.e., apples, bananas, and oranges.
I need to buy fruit, e.g., apples, bananas, and oranges.
'i.e.' means 'that is' (restating); 'e.g.' means 'for example' (listing possibilities).
She enjoys outdoor sports i.e. hiking and skiing.
She enjoys outdoor sports, i.e., hiking and skiing.
'i.e.' is usually set off with commas or parentheses.

Synonym discussion

Sense: abbreviation/1

All four expressions introduce clarification or elaboration, but they differ in scope and use. 'That is' is the full English equivalent of 'i.e.' and is interchangeable in most writing, though 'i.e.' is more compact. 'Namely' is more formal and typically used when specifying items in a list ('three countries, namely Japan, Korea, and Taiwan') — it sounds stiff in casual contexts. 'In other words' signals a full rephrasing of the preceding idea and works naturally in speech and informal writing. 'E.g.' (exempli gratia) is the most commonly confused pair — it means 'for example' and introduces one or more options rather than a restatement. Use 'i.e.' to clarify identity ('the capital, i.e., Taipei') and 'e.g.' to give examples ('Asian capitals, e.g., Taipei and Tokyo').

that isnamely ↗in other words ↗e.g. ↗

Etymology

LatinEnglish

Shortened from the Latin phrase id est, literally meaning 'that is'. The abbreviation entered English in the 17th century as a scholarly shorthand and remains common in formal, academic, and professional writing across both British and American English.