Where did the term English originate in billiards?

Each time you stroke the cue ball to the left or right of center, some degree of english is applied. (Note that english is not capitalized, it has nothing to do with England.)

How much english you get is based on 4 factors - how far from cue ball center contact is made; how long the cue tip stays in contact with the cue ball; condition of the cue tip; condition of the cue ball and pool table playing surface. To increase the amount of english, a soft cue tip is required and the player must accelerate the cue as contact is made with the cue ball, resulting in staying in contact for a longer period. In addition, if you have a cue that you know you will use english with quite regularly, the tip should have the "dime" shape. Cue tips are typically shaped to the curvature of either a nickel or a dime. The shape of a dime allows the tip to stay in contact with the cue ball longer than the nickel shape, improving english.