Now while I know therian and otherkin are terms to describe a long ranging topic with several different views and opinions, you do not have to agree with me nor does any of what I say mean it's true, however from the general consensus of therian and otherkin groups online, the following links should provide an understanding of what a therian and othekin is. Information shall be backed up by online sources for credible purposes.
Otherkin:http://en.wikipedia.org/wiki/Otherkinhttp://www.otherkin.net/articles/what.htmlAs the therian link suggests, there is a difference between therians and furries, therians are much more spiritually and/or mentally involved with the animal they are associated with. This however does not mean that furries cannot be therian or vice-versa, it's just perspectives. Otherkin on the otherhand can also be classified as therians to some degree, but often show different characteristics which is why they are considered another type of their own. Of course this means you can be both therian and otherkin.
Therianthropy Explained:Other things to take into account are that the encyclopedia meaning of "therianthropy"
refers to the metamorphosis of humans into other animals.[1] from n. therianthrope and adj. therianthropic, part man and part beast, from the Greek theríon, meaning "wild animal" or "beast" (impliedly mammalian), and anthrōpos, meaning "human being") Therianthropes have long existed in mythology, appearing in ancient cave drawings[2] such as the Sorcerer at Les Trois Frères. Source:
http://en.wikipedia.org/wiki/TherianthropyThe modern day meaning while not incorrect should not be taken literally when considering
therians and/or otherkin beliefs, it is simply the word that derived their identifing label from. Generally never believed to be manifested physically, this means that online generally the accepted idea is that there are no physical associations to the animal that therians and/or otherkin represent. In example, a wolf therian cannot metamorph into a wolf nor a dragon otherkin transforming into a dragon. This does not mean though that therians will not show any signs of the animal they are like, Therians/Otherkin can show the thoughts, feelings, desires,and even actions between people around them from their animal characteristics. Again this should be noted that Therians and Otherkin should not be identified as furries, because as disrespectful as insults are to people, their beliefs prefer to be named properly in many cases. However if such people find it does not bother them, then it's okay.
Definition of Theriotype - Basically the "type" of animal a Therian is, for example a Siberian tiger would be a single theriotype. Therians can have more than one theriotype, but it is not as common as single types.
Shifting Defined and the Different Types:Shifting is just as much a part of Therian as it is Otherkin, but Otherkin does not generally coin this term with different ideals towards the premise, Therians on the other hand will become more like the theriotype they represent in the form of a change also known as "shift". This shift causing psychological, spiritual, energy, and/or outward appearance to change more appropriately to fit their theriotype. Shifting is not necessarily a required trait to be Therian and should not be taken as such as not all Therians experience shifts.
The different types of shifts are: mental, phantom, astral, dream, physical, and cameo shifts.
More often than Otherkin in general, Therians experience moments of what is known as "shifting" where their psychological, spiritual, energy, and/or appearance will change to more appropriately fit the animal they represent.
Otherkin Explained:Otherkin can more or less consider themselves not human in some manner, where it be physically/spiritually/energetically/mentally etc, the focus of Otherkin resides more on society deemed "mythological" creatures such as elves, angels, demons, werewolves, vampires, faeries, dragons, centaurs etcetera and not limited to these mentioned. Other such characteristics as the feeling of being in the wrong gender, body, or something of a lost nature in this world can be considered Otherkin. Other traits can be strange allergies to certain objects and/or materials, memories not your own *as in you don't remember them actually happening but remember them*, dreams of past lives and/or deaths, thoughts or sights awkward to yourself, and many more things. Source:
http://kinhost.org/res/Otherfaq.php#1_2Not always used or made for identifying Otherkin, the "Acute Heptagram" symbol also known as Faerie or Elven Star represents Otherkin in some places online and elsewhere.
http://upload.wikimedia.org/wikipedia/commons/thumb/8/83/Acute_heptagram.svg/615px-Acute_heptagram.svg.pngFeel free to add any more info to this as I am not 100% knowledgeable, as this was written just for the purpose of understanding, but please provide sources to your information to give it credibility. I will add more information later today as well.