A penny is:
The plural of "penny" is "pence" when referring to a quantity of money and "pennies" when referring to a number of coins. Thus a coin worth five times as much as one penny is worth five pence, but it is not five pennies, since "five pennies" means five coins each of which is a penny. In the USA, "penny" is normally used only to refer to the coin; the quantity of money is a "cent". A coin worth five times as much as a penny is worth "five cents".
See also: