I strongly considered the fact that while typing this site, I'm using very specific phrases and vocabulary. I'm not trying to be a pain, I promise. I thought that a dictionary or list of terms might assist in some of the finer vocabulary details which will hopefully help you get through things! It's meant to be helpful and awesome. If you're already familiar with KHR and know the vocabulary, you'll probably just roll your eyes at me - that's okay too.
Arcobaleno - One of seven elite babies, they represent the strongest of the era. They are the holders of the elemental pacifiers based in one of the seven elements: storm, sky, sun, thunder, rain, mist, and cloud. Coordinate with the rainbow's red, orange, yellow, green, blue, indigo, and violet.
Box Weapons - Weapons invented ten years in the future. They are divided into elements and opened with corresponding rings.
Dying Will - The will that symbolizes a person's last thoughts or desires before dying. Fighting with your dying will is akin to giving it everything you've got. Sometimes this is also called deathperation. Frequently used to describe the energy of a person's attacks. It is essentially a person's life force.
Elemental Flame - A type of dying will flame based in one of the seven elements: storm, sky, sun, thunder, rain, mist, and cloud. Coordinate with the rainbow's red, orange, yellow, green, blue, indigo, and violet. Sky is the most important flame it is the strongest. Xanxus is a sky element, which means he has an orange flame. Most boss characters or people in leadership roles are sky element.
Flame of Wrath - A very destructive sky flame with storm like properties. Thus far, only Ricardo and Xanxus are recorded to have this type of flame.
Sky Flame - A type of dying will flame based in the sky element; usually held by bosses or the heads of families, the flame is orange.
Varia - An elite assassin group within the Vongola family. They have a very high success rate in completing their missions. They are so good in fact, that it pays to be Varia Quality. They're a bunch of ruthless jerks that have no qualms about killing family members, hitting women, or trying to kill teenagers over jewelry.
Vongola - The strongest mafia family. They are currently looking for the tenth boss.