A partial tang stops somewhere short of the butt of the handle. The steel extends far enough to anchor the blade securely but does not reach the end of the grip, which saves weight and cost at the price of leverage strength.
Cut a partial-tang knife in half lengthwise and the steel would stop part way down the handle, with handle material filling the rest. The join is usually invisible from outside, which is why the spec line matters more than the look.
Partial tang covers a wide range. Some stop just past the first pin. Others run most of the handle and only fall short of the butt. Manufacturers do not always distinguish, so treat "partial" as "less than full" rather than as a precise measurement.
Plenty of excellent working knives are partial tang. Traditional kitchen knives, fillet knives and light utility blades all benefit from the reduced weight, and none of them are meant to be levered.
Where it becomes a real limitation is impact and prying. If your intended use includes batoning through wood or working a stuck blade free sideways, choose full tang instead. The failure point on a partial tang is the transition where the steel ends.