The definition of a sign will always be one of a great encompassing level since we are referring to an element that can be used in infinite areas of human language to symbolize a meaning, meaning that can in turn vary on each occasion. Although the notion of sign tends to be related to certain types of elements (for example the signs of the zodiac, punctuation marks), a sign can be any representation of human language in its immense variety.
The sign, understood as an abstract entity, has been created by the human being to symbolize different types of concepts in different ways. This is why the sign always refers to another entity, which is why it is argued that a sign is always dependent on another element, the one it is symbolizing, although its meaning may vary endlessly. This dependency relationship is what we know as significance, the moment in which the sign and the entity to which it refers are joined.
The signs are constructed for various purposes, methods, and styles. Some types of most recognized signs are those that are established in the language (each letter or symbol of an alphabet is a sign, as are punctuation marks or communication signs established for people with hearing disabilities), religious signs and those that represent another style of beliefs or thoughts, such as the signs of different zodiacs, traffic and transit signs that are used to organize vehicular movement, computer signs (in high diffusion since the second half of the 20th century) or information signs.
However, the term sign can also refer to an element through which a causal relationship can be established with a result. For example, a sign in this sense can be a physical symptom that is analyzed to diagnose a disease, or a sign of meteorological behavior can be used to foresee future events.
