I'd still argue it's all gambling, even though there are many safe and boring bets. We can't guarantee Gold won't be obsolete in 40 years or thst we find some insane vein or synthesis process that deflates the value. We can't guarantee we hit some depression right when you want to cash out.
Leaving your money to banks with the hopes you end up on top is pretty much gambling no matter what. Even if it's safer than most traditional gambling.
It does fit the second dictionary definition of gambling: "take risky action in the hope of a desired result". However at that point almost everything you do in life could be called 'gambling' so it kind of loses all meaning. Buying a Big Mac? Gambling that it isn't infected with e coli. And so on.
Leaving your money to banks with the hopes you end up on top is pretty much gambling no matter what. Even if it's safer than most traditional gambling.