format

noun: a way in which data is represented and stored.

I think of a format as a pattern that fits over the data and gives it meaning.

A special case of a format (noun) is a file format.

For`mat" (fOr`ma" or fOr`mät"), n. [F. or G. Cf. Formation.] (Print.)

The shape and size of a book; hence, its external form.

The older manuscripts had been written in a much larger format than that found convenient for university work.
G. H. Putnam.

One might, indeed, protest that the format is a little too luxurious.
Nature.

© Webster 1913