It is important to underline in the first place that the bilateral term that we are now dealing with has its etymological origin in Latin, as evidenced by the fact that it is made up of several Latin elements. Specifically, it has been created from the sum of the following parts: the prefix bi – which can be translated as “two”, the word latus which is equivalent to both “side” and “wide”, and the suffix -al which is synonymous with “relative to”.

According to DigoPaul, bilateral is defined as that which belongs to or refers to a pair of sides, parts, sides or aspects of the same thing. In this sense, it is possible to speak of bilateral relations or ties that arise between two nations or entities. For example: “The chancellor promised to reestablish bilateral relations with the neighboring country”, “The judge analyzes the bilateral agreement to determine if it is framed within the provisions of the Constitution”, “Hungary and Slovenia have signed a bilateral agreement to the exchange of scientific knowledge ”.

The bilateral contract, on the other hand, is one that, according to the Law, generates reciprocal obligations between the parties involved. A company that distributes mineral water and another dedicated to providing Internet services establish a bilateral contract through which the former undertakes to deliver 100 liters of mineral water per month and the latter to provide the connection service. In the event that one of the two does not comply with the provisions (that is, the first company does not deliver the water or the second does not provide the connection), the bilateral contract will have been violated.

In this sense, we cannot ignore the fact that in Spain there are also what are known as bilateral cooperation commissions. This is the name that is given to all those relationships that exist between the corresponding autonomous communities and the central government to analyze, develop and make agreements that deal with matters that interest both parties.

These “meetings” have been taking place in that country since the 1980’s and some of them have already been clearly specified in the autonomy statutes. A clear example of this are the communities of Andalusia, Catalonia, Aragon or Castilla y León.

In the field of Health and Medicine, we also have to underline the use of the term that we are now analyzing. Specifically, in this sector we talk about what is known as bilateral mammography. This is neither more nor less than the X-ray of both breasts of a woman to be able to determine the state in which the breast tissue is.

For Biology, on the other hand, the idea of bilateral or planar symmetry is reserved to describe the conformation of a plane (known under the name of the sagittal plane) that marks a division in the body into equal halves: one left and the other, right. If the plane were perpendicular, it is known as the frontal plane and it divides the organism into the dorsal half and the ventral half.

Humans and most animals have bilateral symmetry, which contributes to the formation of the centralized nervous system and cephalization.