Not just technically, but in actuality!
The rule says that a batter becomes a batter-runner when the third strike is not caught...etc, etc, etc. Calling it a dropped third strike implies that it had to have been caught first, before it could be dropped.
That's not the case. All the rule requires is that the ball be cleanly caught to complete the out out. This "catch" has to meet the same definition as a caught fly ball. That is, it must be airborne, or in-flight, from the pitcher's hand to the catcher, the same as a batted ball must be to be caught for an out. The ball can't bounce before it's caught, and it cant touch anything other than the catcher, like the batter or the umpire.
People do commonly refer to this as a "dropped" third strike. In fact, the rule book even calls it that in some places where it refers to the rule. Even though that term is technically wrong, we know what they really mean.