A primary meaning of "free" is "not under the control of others." Someone with choices and liberty is free, whereas someone in slavery isn't. A nation or territory is also defined as free when it operates independently from the control of another nation or government.
Another meaning of "free" is "unobstructed" or "loose," such as when a person's leg is freed from under a tree branch. "Free" is also used as a synonym for "unoccupied" or "open for use." "Free" can also mean that something is available at no cost. A company might offer a free sample of a product to entice someone to purchase additional amounts.