The plain-English definition
Alternative investments generally refer to assets, funds, and strategies that sit outside the traditional mix of public stocks, public bonds, and cash products. In practice, that umbrella can include private real estate, private credit, venture and startup investing, crypto, farmland, art, wine, collectibles, hedge-fund-style vehicles, and other less standardized structures.
That broad definition is useful for orientation, but it can also hide the most important truth: alternatives are not one thing. A diversified evergreen real-estate fund, a short-duration private-credit note, a hardware wallet for self-custody, and a fractional art platform may all appear on the same site while behaving nothing alike.