In the Greek it is where we can find the etymological origin of the word that we are now going to analyze, kilogram. Specifically, based on this premise, it can be established that this term is made up of two clearly differentiated parts that give rise to its meaning. Thus, it is composed of *kil *which is equivalent to “thousand” and *gramma *which can be translated as “stone to weigh.”

It is known as **kilogram** to a **unit of mass** contemplated by the **International System of Units**. It is roughly equivalent to the **dough** thousand cubic centimeters of water conserved at the temperature of its maximum density (4ºC) and the mass of a cylinder of platinum-iridium stored in the **International Office of Weights and Measures** located in the French city of **Paris**.

It should be noted that the kilogram, which is represented by the abbreviation **kg**, is the only unit belonging to the International System that is still established from a pattern object, that is, it does not take into account a fundamental physical characteristic. The kilogram (also referred to as **kilo**) also refers to the amount of some material that can be measured by kilograms. For instance: *“I’m going to take a kilogram of roast”*, *“I need ten kilograms of lime”*.

In addition to all the above, we cannot ignore either that this unit that we are dealing with has a series of multiples and submultiples. Thus, among the former are the decagram, the hectogram or the ton while in the case of the latter are the decigram or the centigram, among others.

With regard to equivalences, it must be emphasized that the kilogram, for example, is equal to one million milligrams, 10,000 decigrams, 1000 grams or 10 hectograms.

It is important to note that the definition of the kilogram has varied throughout history. During the **French Revolution**, it was stipulated that one kilo corresponded to the mass of a cubic decimeter of distilled water at an atmosphere of pressure 3.98ºC.

To avoid the problems that this measurement entailed (since the density of this fluid is conditioned by pressure and this considers mass as a factor), the kilogram was redefined from a **particular standard mass** which was created as the most exact approximation possible to the original definition. That mass corresponding to the international prototype of the kilogram is the alloy of platinum (90%) and iridium (10%) found in **France**.

Still attempts are being made, anyway, to formulate a definition of kilogram from **physical laws**. Scientists around the world are conducting tests to that end.

We cannot finish this definition of the term kilogram without stating that it is closely related to what the kilopond or kilopond force is. In the field of science, and more specifically of Physics, it is where this last word is used, which is defined as a unit of force within what is the Decimal Metric System.

Specifically, the kilopond is equivalent to the force that acts on a mass of one kilogram that is subjected to what is a situation of normal gravity.