Idem vs. Ditto — What's the Difference?

Idem is a Latin term meaning "the same". It is commonly abbreviated as id., which is particularly used in legal citations to denote the previously cited source (compare ibid.).

The same as stated above or before.

Used in citations to indicate an author or word that has just been mentioned

A duplicate; a copy.

The same.

A pair of small marks ( " ) used to indicate that the word, phrase, or figure given above is to be repeated.

The same; the same as above; - often abbreviated id.

As before.

To duplicate (a document, for example).

That which was stated before, the aforesaid, the above, the same, likewise.

A duplicate or copy of a document, particularly one created by a spirit duplicator.

(by extension) A copy; an imitation.

The ditto mark, 〃; a symbol, represented by two apostrophes, inverted commas, or quotation marks (" "), indicating that the item preceding is to be repeated.

A suit of clothes of the same colour throughout.

As said before, likewise.

(transitive) To repeat the aforesaid, the earlier action etc.

(US) To make a copy using a ditto machine.

Used as an expression of agreement with what another person has said, or to indicate that what they have said equally applies to the person being addressed.

The aforesaid thing; the same (as before). Often contracted to do., or to two "turned commas" ("), or small marks. Used in bills, books of account, tables of names, etc., to save repetition.

As before, or aforesaid; in the same manner; also.

A mark used to indicate the word above it should be repeated

Repeat an action or statement;