Weighted as in with a key action simulating the hammers of a piano (to some extent). Most weighted keyboards are also, as you say, graduated from the lowest to

Weighted as in with a key action simulating the hammers of a piano (to some extent). Most weighted keyboards are also, as you say, graduated from the lowest to the highest note. Weighted keyboards are easier to play expressively, because the added mass allows you to impart velocity onto the key over a period of time. A non-weighted keyboard effectively reacts to how fast/hard you move your finger, with little resistance, while a weighted keyboard integrates how much force you apply to the key over the milliseconds it takes to press it. It makes a difference. It also means you can "launch" keys without having to apply force all the way down, and inertia will take it there. On the other hand, if you're playing with organ sounds of synths, a non-weighted keyboard lets you do faster glissandos and faster key repetition and rhythmic playing. So it depends on what you're doing and what you're used to.