A pictogram or pictograph is a symbol which represents a concept or an object by illustration.
Early written characters were based on pictograms and ideograms, it is commonly believed that pictograms appeared before ideograms. Pictograms remain in common use today; for example the symbols on public toilets for "men" and "women."
Because pictograms do not depend on language, places such as airports and train stations use them for signposting. However, they can depend on culture—in the case of toilets, in some cultures men commonly wear dress-like clothing.
A standard set of pictograms was defined in the international standard ISO 7001: Public Information Symbols. Another common set of pictograms are the laundry symbols used on clothing tags.
See also: Pictography, emoticon, Writing system