A cultivar is a strain of plant that has unique characteristics, it doesn't have to be a hybrid. For example there are many diifferent cultivars of the Venus flytrap. There's the B52, Red Dragon, Red Line, & so on.

Although you are more likely to get a plant with special characteristics when hybridizing. For example the hybrid Sarracenia x wrigleyana, a hybrid between S. psittacina crossed with the leucophylla, there's a popular cultivar named 'Scarlet Belle' because this particular hybrid makes makes huge colorful hoods.

To maintain a cultivar, usually the plant are propagated by vegetative means, that means not by seed because the progeny looses that uniqueness. But it depends on the cultivar if they can be propagated by seed or not.

Here's a site that can help you what you can register a cultivar: http://www.carnivorousplants.org/cultivars/cultivarsmain.php

With sample cultivar registration: http://www.carnivorousplants.org/cultivars/register.php

Good luck!