Simply put, a unit trust fund is a way for you to invest your money. You can invest in a unit trust fund through financial services providers such as a broker; an Investment Management Company or in some cases through your bank. A unit trust fund is a pooled resource, which means that it allows a group of investors to combine their cash and invest it. Think of it like going in on a group gift. Taken altogether, those investments are called the fund's assets.
While you as an individual invest in a unit trust fund, the fund itself is run by a fund manager, whose aim is to grow the overall value of unit trust fund. The fund manager does this by investing the fund's assets, usually by buying stocks, bonds, or a combination of these two securities which are listed on the Stock Exchange. (Some unit trust funds can buy more complicated security types.) These stocks or bonds are often referred to as a fund's "holdings" and all of a fund's holdings together are its "portfolio."