What is the X in X-mas?
c.1300, "physical strength," from Old French force (12c.) "force, strength, courage, fortitude; violence, power, compulsion," from Vulgar Latin *fortia (cf. Spanish fuerza, Italian forza), noun use of neuter plural of Latin fortis "strong" (see fort). Meaning "body of armed men, army" first recorded late 14c. (also in Old French). Physics sense is from 1660s; force field attested by 1920.
The capacity to do work or cause physical change; energy, strength, or active power.
A vector quantity that tends to produce an acceleration of a body in the direction of its application.
In physics, something that causes a change in the motion of an object. The modern definition of force (an object's mass multiplied by its acceleration) was given by Isaac Newton in Newton's laws of motion. The most familiar unit of force is the pound. (See mechanics.)
Note: Gravity, and therefore weight, is a kind of force.