It's been spelled Taekwondo, Taekwon-Do, Tae Kwon Do, and TaeKwon Do, but, essentially, the word for the martial art boils down to three parts in the original Korean: tae, meaning "to kick" or otherwise cause damage with your foot, gwon, meaning "to punch", and do, meaning "the way". Together, this is interpreted as meaning "the way of kicking and punching". Asian etymologies are really hard for me to do, because they combine parts of characters and can't really be traced the way English ones can, so I won't comment further on something I don't know much about. However, let's talk about form. Of all the capitalizations and spellings since the word's introduction in the 1960s, the different capitalizations of taekwondo and Taekwondo are about tied for usages, in both literature and Google searches. The other terms exist but are less frequent.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd