Abbreviation is defined as a shortened form of a word or phrase. Generally, it is usually one or more vowels or consonants taken from the word or phrase and used to summarize expressions. There are no rules for its use, although it is common to remove the letters from the center or the end and leave only the essential ones for the word to be understood. An example of an abbreviation could be: Admon. = Administration.
The word abbreviation comes from the Latin brevis, and sometimes they share semantic and phonetic functions with contractions, acronyms or acronyms but their use is different so they should not be confused with each other.
These types of constructions are widely used to abbreviate scientific units such as: 10 degrees Celsius = 10°C. In these cases, no space is usually added between the number and the unit.
There are examples of abbreviations from ancient times, so it could be said that they have a long history. The Phoenicians, the Greeks, the Romans... used them to avoid spelling an entire word and thus be able to reduce space in their writings in this way they saved time and material. Abbreviations were also used as a form of secret communication. In ancient Rome the words were abbreviated in a very usual way and many of the inscriptions came to have at least one abbreviation, an example of this is the letters SPQR which meant "the Senate and the people of Rome" and represented the power Rome politician.
Many symbols that were used in ancient times have remained in modern scripts and today it can be said that this type of construction is used in almost all languages.
On many occasions, the abbreviations do not have a plural form and the context allows us to find the exact meaning of the word, but as mentioned above, in reality there is no specific rule for the use of these word constructions, so some writers add an "s" to pluralize abbreviations. It is also common for abbreviations formed by a single letter to form the plural by doubling it. An example of this formation would be (RRLL for labor relations or USA for the United States).