It is a respectful title for the elderly.

Fund is an indirect investment, that is, your money does not directly buy goods, but is given to a professional to help you buy them. In this way, it's a bit like purchasing on behalf of others. Of course, unlike purchasing on behalf of others, you can't specify what the professional will buy for you (generally you won't do this, so why would you want him to do it if you understand), but he will tell you. He will probably buy those things, what are the risks and so on.

So, in fact, a fund is a trust relationship. You entrust a professional organization (fund management company), which is entrusted by you to help you manage your funds and make investments.