Before determining the meaning of the word disjunction, it is interesting that we clarify its etymological origin. Specifically, we can say that it emanates from Latin, and more precisely from the word “disiunctio”, which is the result of the sum of three components: the prefix “dis-“, which is equivalent to “separation”; the noun “iunctus”, which can be translated as “united”; and finally the suffix “-ción”, which is synonymous with “action and effect”.

Disjunction is the action and effect of disuniting and separating. The concept is used in various fields, such as genetics, the grammar and the philosophy.

DisjunctionThe genetic disjunction is the separation of chromosomes through the processes of mitosis (the division in which each cell daughter receives a full set of chromosomes after duplication of genetic material) or meiosis (the succession of two cell divisions in the process of the formation of gametes, which results in four cells where each one has a chromosome from each pair of the original cell).

In the grammar, is known as disjunction or disjunctive conjunction to word (or set of them) that indicates an exclusive or exclusive alternation. The expression “Let’s go to Miami or Punta Cana” presents the disjunction “or”, while the phrase “Choose between Pedro or Oscar” includes the disjunctive conjunction “or”. Other examples of these conjunctions are “Do you want hot dogs or hamburgers?”, “I don’t know whether to call the manager or the CEO.”, “We have to think about the car or another good to pay off the debt”.

For the rhetoric, the disjunction is a figure that is formed when each sentence carries all its necessary parts, even when none of these sentences is necessary for the meaning of the preceding one or the next.

It should not be overlooked that within Earth Sciences the use of the term that we are now analyzing is also used. Specifically, in this field there is talk of what has been called columnar disjunction, which is a rupture of the rocks that occurs as a result of stresses arising from the fact that the lava has cooled.

On the Portuguese island of Porto Santo, located about 40 kilometers from Madeira, you can see, for example, various columnar disjunctions in the basalts that are part of its landscape.

The Dphilosophical isjunction it implies the separation of two realities, even though both are intrinsically related to each other (up / down, right / left, etc.).

The logical disjunctionFinally, it is the statement that is true when any of the operators is true.

Precisely within this last sector, we would have to make it clear that there is a type of logical disjunction that receives the name of exclusive disjunction. We can determine that it is defined by the fact that it consists of two operands and that it will be true if only one of these two is true.

This type of disjunction, also called exclusive, is usually represented by various symbols, including EOR, XOR or EXOR.