The Chinese character "Jin" (勁) is the combination of "Jing" (巠) and "Li" (巠). Its meaning derived from the character Li and the sound from Jing. The word Jing means water veins, and the structure of this Chinese character symbolized water flows from high level to low level and then goes underground.
The word Li has 5 basic meanings:
1. Force, cause the motion or change the moving direction of an object; basically it has 3 properties: it has different level of intensity; it has direction; it has focus
2. Power; energy: man power; intellectual power; material power; fighting power; power of reasoning; power of persuasion
3. Physical strength: man of physical strength; there is no physical strength in the limbs; use one's physical strength to push a car
4. Do all one can; make every effort: fail to do all one can at work; make every effort to strive to the top
5. This word is also use as a surname but take note that there are other words that has the same sound
The word Jin has 4 basic meanings:
1. Strength; energy: put forth strength; she seems to have inexhaustible energy; I am feeling very weak, without any strength
2. Vigour; spirit; drive; zeal: maintain the same vigour as in the year of revolution; hardworking spirit
3. Manner; expression: look at his haughty expression
4. Interest: he has no interest in playing chess
The meaning of Li can be just a single force or more than one force, as it can be singular or plural in Chinese. The meaning of Jin in Martial Arts can be simply a holistic view of forces within the human body or just a combination of forces. The kinetic chain or the 9 sets of joints of Xingyiquan are good examples of analyzing Jin.