A hybrid is a cross breed between two different breeds, varieties, species or subspecies (between two genetically distinct individuals, that is). The breed is a result af sexual reproduction and its characteristics (for instance, flower colour and leaf shape) are unpredictable (pollination -> fertilization -> seeds within a fruit).

Horticulturally speaking, a cultivar is a cross breed or hybrid as well, but a result of careful selection for special characteristics that can be maintained (inherited by the offspring) by propagation. To maintain the characteristics of a cultivar, you often (but not always) have to use asexual propagation, grafting. A few adenium cultivars (for instance, Adenium arabicum "Golden Crown") come true from seed.

But wouldn't there still be cross polination between surrounding plant and then the seeds may not come true. Or maybe that would be after I grew it and got seeds.

No matter how they are pollinated. They will not come true to seed.

Open pollination is always a possibility if you grow different adeniums in a confined space.

Rick, well, some traits are stable/inherited because of their dominant genetically makeup. Breeding plants are no different from breeding dogs. ;-)

But of course sexual reproduction will always produce offspring different from the parents. It is the very nature of sexual reproduction. By "come true" I meant that certain stable traits are inherited. Flower colour and shape are a different matter.