Real Dictionary

force
Forces are groups of soldiers or military vehicles that are organized for a particular purpose.
You can use forces to refer to processes and events that do not appear to be caused by human beings, and are therefore difficult to understand or control.
countable noun: If you refer to someone or something as a force in a particular type of activity, you mean that they have a strong influence on it.
plural noun: The forces means the army, the navy, or the air force, or all three.
singular noun: The force is sometimes used to mean the police force.
uncountable noun: Force is the power or strength which something has.
uncountable noun: Force is used before a number to indicate a wind of a particular speed or strength, especially a very strong wind.
uncountable noun: If someone uses force to do something, or if it is done by force, strong and violent physical action is taken in order to achieve it.
uncountable noun: The force of something is the powerful effect or quality that it has.
variable noun: In physics, a force is the pulling or pushing effect that something has on something else.
verb: If a situation or event forces you to do something, it makes it necessary for you to do something that you would not otherwise have done.
verb: If someone forces a lock, a door, or a window, they break the lock or fastening in order to get into a building without using a key.
verb: If someone forces something on or upon you, they make you accept or use it when you would prefer not to.
verb: If someone forces you to do something, they make you do it even though you do not want to, for example by threatening you.
verb: If you force a smile or a laugh, you manage to smile or laugh, but with an effort because you are unhappy.
verb: If you force something into a particular position, you use a lot of strength to make it move there.

force in American English
strength; energy; vigor; power
noun: physical power or strength possessed by a living being

force in British English 1
noun: strength or energy; might; power

force in British English 2
noun: (in northern England) a waterfall

force in Mechanical Engineering
noun: A force is an action applied to a body which makes it change speed, direction, or shape.