The word "for" is a preposition that helps us express purpose or reason. For example, when we say, "I bought flowers for my friend," it shows that the flowers are intended as a gift for my friend. It connects the action of buying with the reason behind it. Additionally, "for" can indicate a duration of time. When someone says, "I will be here for two hours," it tells us how long they plan to stay. In this case, "for" links the action of being present with the specific time frame of two hours.