It is called logogram to the sign what, by itself, can represent a meaning. The usual thing is that the logogram allows the representation of a word.
It can be said that a logogram is a grapheme: the minimum writing unit of a certain language. Graphemes cannot be divided: in the roman alphabet (also know as latin alphabet), therefore, they are equivalent to letters.
The logograms represent morphemes, lexemes or, as we already said, words. In this way they differ from ideograms and the pictograms, for example.
The key to logograms is in the use of visual elements. They do not appeal to segment phonemes (as with alphabets), but rather order visual components in various ways to produce meaning. At a general level, it is simple to deduce or remember what a logogram means; Furthermore, given its characteristics, different tongues they can share similar logograms.
The characters that are used in the Chinese writing they are often referred to as logograms. They were born from an iconic relationship with what they designate and then, over the years, they they stylized and they adapted to conventions.
What these Chinese logograms do is refer to a meaning (present in the language), which is responsible for pointing out a extralinguistic reality. Therefore, the logogram does not represent the object directly.
Despite the simplicity of understanding logograms, their own characteristics make them exist numerous signs. It takes a huge number of logograms to make a idea in writing, which makes learning the language in question very complex.