Ditto MarksDitto Marks — illustrated emblem for the Mr. B Quotes glossary, category Punctuation & StyleDPUNCTUATION & STYLE
Punctuation & Style

Ditto Marks

The ″ symbol used in lists to mean 'the same as the line above' — not a quotation mark.

Ditto marks indicate repetition in tabular or list material: a line entry repeats the value directly above it. The mark is written centred under the repeated text, traditionally as a double prime (″) or a pair of straight apostrophes in typewriter practice.

They are frequently confused with quotation marks and with inch marks, because all three have been typed with the same key. In careful typography they are distinct characters with distinct purposes, and only quotation marks should be curly.

Modern style guides discourage ditto marks in running prose and in published tables, on the grounds that repeated values are clearer than a symbol whose meaning depends on vertical alignment — an alignment that breaks in responsive layouts and screen readers.

Common mistake: using ditto marks in a data table that will be exported or read aloud. Repeat the value; accessibility tools cannot infer what the mark points to.

Example
Oats, 2 kg Barley, ″
illustrative usage · The second line means '2 kg'; in published work you would simply repeat the quantity.
Related terms

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