Both
@Arson and
@FoxyAnimations provided excellent answers to these questions. I am just adding emphasis here to the point made about "kith" or "heart-type", mostly because the depth of the language that really should be associated with it.
As stated to have a "heart-type" or to be "kith" to something is to first recognize it as not oneself but a deep bond to that thing. This bond is no ordinary bond or fascination either, it needs to be absolutely consuming and heartfelt to be regarded with greater certainty. It is too easy to like or even love something and just be infatuated with it, it is another to have an affinity for it. It often takes a purely irrational draw and passion for it, an association, which is separate but reflective of it. What I mean by this is, is that it is not only oneself, but it is an external motivating factor and connection to it; one's self is not forcing it to happen.
A great number of people love cats but a large number of those people force their love upon cats. They are not receptive to this and often shy away or similarly, their commitment is purely obsessive such as hoarding behavior, or over-grooming, or any number of these things. They often develop grand collections of things which are material items from their transfixed focus. They often negate or neglect or ignore more meaningful or real problems. On and on could this list go, but this is not what a "heart-type" is. Such a thing instead is a deeper, more sincere, less tangible, less cognitive, and far more elusive but extreme affiliation with and draw toward; magnetic, as some might frame it. There are often, as well I will share, tones of being bonded with and by the very thing in return where there is an unnatural understanding between both almost that is much more outside the pragmatic or obsessive norms, a type of mutualism or appreciation.
One way I could describe it is, is loving something so conceptually that one would do anything for it as one would themselves, but that is merely my experience. To what lengths I will go, irrationally, for felines, for example, and the ability to bond with them is by no means normal. I have no other relationship with any other organism, to include people, but the sheer depth of my connectivity to felines is so strong it is part of how I oriented the entirety of my life toward them and in many cases, interact directly with them. No less, in this case, the animals respond, because of that aforementioned sense of some type of mutual bond. Barring in mind that in this example toward myself, this is with exotic cats, from scrawny six pound feral cats to six-hundred pound tigers.
I can only call it a sort of nexus of affinity-bonded, mutualistic, selfless, irrational love. It certainly is not the average variety when referring to this kind, as the term "heart" should imply in it. Really between it, "kith" should truly be considered the external form of "kin", because it operates similarly (such as not being chosen, being deeply inner and personal, having this sort of cyclic relation) but as said above they are not the same. "One is
kin, and one is
kith to."
