Prefixes are key morphemes in English vocabulary that begin words. The English prefix *ad-* means "to, towards." Examples using this prefix include [*ad*]mit and [*ad*]just. An easy way to remember that the prefix *ad-* means "towards" is through the word [*ad*]vertise, for when you [*ad*]vertise you try to turn potential buyers "towards" the product you are selling.