The main difference between Ideogram and Pictogram is that the Ideogram is a graphic symbol that represents an idea or concept and Pictogram is a ideogram that conveys its meaning through its pictorial resemblance to a physical object.
An ideogram or ideograph (from Greek ἰδέα idéa “idea” and γράφω gráphō “to write”) is a graphic symbol that represents an idea or concept, independent of any particular language, and specific words or phrases. Some ideograms are comprehensible only by familiarity with prior convention; others convey their meaning through pictorial resemblance to a physical object, and thus may also be referred to as pictograms.
A pictogram, also called a pictogramme, pictograph, or simply picto, and in computer usage an icon, is an ideogram that conveys its meaning through its pictorial resemblance to a physical object. Pictographs are often used in writing and graphic systems in which the characters are to a considerable extent pictorial in appearance. A pictogram may also be used in subjects such as leisure, tourism, and geography.
Pictography is a form of writing which uses representational, pictorial drawings, similarly to cuneiform and, to some extent, hieroglyphic writing, which also uses drawings as phonetic letters or determinative rhymes. Some pictograms, such as Hazards pictograms, are elements of formal languages.
Pictograph has a rather different meaning in the field of prehistoric art, including recent art by traditional societies and then means art painted on rock surfaces, as opposed to petroglyphs; the latter are carved or incised. Such images may or may not be considered pictograms in the general sense.
A picture or symbol which represents the idea of something without indicating the sequence of sounds used to pronounce it. Examples include digits, traffic signs, and graphic symbols such as @.
A picture that represents a word or an idea by illustration.