The lexicon is known as the inventory of the units that make up a language. When you talk about the vocabulary of a language you are referring to the total set of words in it, in other words, to its lexicon. This is a term that is widely applied in the study of linguistics and its forms to define the way people speak. The lexicons are generally the forms of expression of the language in a certain social group.

The lexicon of a language, obviously, is an open set, as it is constantly being enriched with new words, either because we speakers of that language invent them, or because we borrow them from other languages. Also, the lexicon of a language changes quickly or slowly according to the geographical, political or cultural changes in which the speakers participate. Not everyone speaks or writes the same in all regions and countries.

Most of the Spanish lexicon comes from the Latin spoken during the time when the Romans ruled the Iberian Peninsula. These words from Latin that have evolved throughout history are what make up the call patrimonial lexicon. These words were later joined by the contributions of other languages ​​such as Greek, Arabic, among others; which are known as language loans.

There are also the so-called technicalities, which are the terms of a certain profession, science, activity or area of ​​knowledge. The lexical terms that every language has are collected in the dictionary. Each one of the individuals of a linguistic community does not possess, nor knows nor uses in equal measure, the arsenal of lexical richness of their language. When it is said that a person has a “rich” or “poor” vocabulary, the partial total of words that person knows is being related to the general total of the lexicon, the two quantities are being implicitly compared.

For example, Maria has a poorer vocabulary than Pedro, because Maria knows fewer words. The important thing is that the total number of words in the language, with which the comparison is made, is the same. And that such a comparison between the two people cannot be made between two languages ​​because each of them will have a different lexicon, but in no case, richer or poorer than the other.

Lexicology is the study of the lexicon of a language and the way it is formed, it is also the study of the resources that we have to enrich the lexicon. Another discipline also related to the lexicon is lexicography, which applies the theoretical concepts provided by lexicology in the making of dictionaries.

The lexicon is an important representative of the identity of a specific place, that is why the study of linguistics has given it an inexorable classification over time, in order to discover the phenomenon that occurs in it. The passive lexicon is one that depends on the understanding of the speaker and the listener, it may not be fully understood by everyone, these may be scientific and experimental lexicons, which are only handled by those who study scientific matter.

The active lexicon, on the contrary, is all that language used in everyday life, I mean that which is constantly enriched by colloquial jargon and which is perfectly understandable by the society that acquired it.