Pictograms are public symbols,they are used to convey information through their resemblance to a physical object or place.

There is no connection between the spoken word and the object pictured. A pictogram recalls the object or concept itself to mind, not its name.

That's what makes pictograms international.

Pictograms represent objects and places

Ideogram is a simplified picture that is selected by agreement or custom to become fixed pictorial symbols of an object, idea, or concept.

The name of the object (or its action) is closely identified (associated) with the picture.

Ideograms represent actions, ideas, or concepts.

Icons represent objects and their functions.

The name of a function (computer program, app) is substituted with a symbol that is recognizable and logical.

The most common use of icons in on digital devices.

Icons represent objects and/or their functions.

Rebus is a symbol that represent spoken sound, word or a part of a word.

Pictures that represent that sound or word have a completely unrelated meaning than the sound they represent in a rebus. For example: "B", "Bee", "be" sound the same and can be used in a rebus to substitute one another.

Most rebuses function only in one language and do not translate into another.

Some exceptions apply though - there are few international symbols that can be used in a rebus.

Rebus uses pictures to represent sounds, words, or parts of words.

Phonogram is a symbol that represents a spoken sound.

Every letter in Latin or Cyrillic alphabet is a phonogram.

Phonogram represents a spoken sound.

Logo is a type of symbol used to represent a brand and to promote products and services. 

Logo's job is to quickly identify and tell the story about a company, a service, a product, an idea, or an individual.

Logo is a unique symbol that identifies a company.

Wordmark consists only of text, often stylized using a unique font. 

Text-only logo styles are an excellent choice for smaller companies who are just starting their business and need to have their name out.

Lettermark is an abbreviation of a company name.

Initials will help you simplify your logo design, especially if the name is a long one..

Brandmark is a pictorial symbol of a company.

Combination marks ( also known as iconic logotypes) - is a combination of an icon (brandmark) and the company name.

Icon and text are positioned next to each other and can be used separately.

Emblems hold text inside of a symbol so that the two are practically inseparable. Text is a part of the symbol.