Terminology
Some terms specific to the campaign setting are listed here.
BEASTIAL: Also known as "beastfolk", the term refers to humanoids that deviate a great deal from dwarves, elves, gnomes, goblins, humans, and orcs, namely those with animalistic features such as full-body fur, hooves, horns, claws, scales, tails, wings, fins, etc. Beastial is a neutral term but "beastfolk" is sometimes seen as pejorative, though more rural folk use the term in a neutral fashion.
CASTER LEVEL: Your "caster level" is just your level regardless of class or racial hit dice. If you're proficient with the school of magic you're using, you get a +3 proficiency bonus to caster level and Concentration checks when using.
FAILURE CHANCE Some actions have a % chance they automatically fail, rolled before any other rolls are made for the action. If the action fails, all costs invested (actions, MP, material component costs, etc.) are still expended but the action does not take place. In addition, those attempting to activate the effect suffer an increase in failure chance to try the same effect on the same target by 5%. This has no maximum increase and continues to accumulate until they succeed on that target. If it goes to 100% or more, they'll continually automatically fail (and worsen this %) every attempt thereafter. If the effect is a resurrection or dispelling effect, there's also a chance every failed attempt will create a curse on the target that applies the increases failure % to anyone else attempting it on them, not just you.
HIT DICE: Every level comes with a hit die so "hit dice" and "level" are now synonymous.
IMMORTAL: Any creature that cannot be killed, or is near-impossible to kill is called "immortal" in passing, but true immortals are those who simply re-appear after death.
IMPERIAL: Imperials or "Imperial Race" is a term used to refer to races that have more urbanized societies, more advanced technology, and tend to expand their territory at the expense of other races. Most humans and dwarves are assumed to be imperial races. Gnomes and elves are also debatably considered among imperial races depending on which ones you’re referring to. High elves are classically considered imperial but wood elves and dark elves are not. Wildlings will often use the term “imperial” or “imp" or "impy" as a pejorative to refer to an imperial race or someone who has betrayed the Wild or gone soft.
INCARNATE: The legendary people known as incarnates are seemingly mortal, but reincarnate into a new body after death rather than passing on to the beyond. Depending on the nature of their death, there may be a delay with the transfer, but eventually they are reborn in a new mortal body. Most regain their memories and powers of former lives over time, often becoming slightly more powerful with each incarnation.
KASHA: The official term for the catfolk race. Bakeneko are a small-sized subrace.
KOBOLD: The official term for the ratfolk race. Unlike other d20 games, kobolds are not reptilian, but some of their mages often use shapeshifting to mimic other humanoids or even elementals.
LINE OF SIGHT: Line of sight means you can perceive the target with a precise sense, even if it's not literal sight (example Blindsight: Echolocation counts as having a line of sight if you can hear the target).
POWER: Spells, spell-like abilities, and supernatural abilities are all types of powers.
SAURIAN: The official term for the lizardfolk race.
TIER: Spell levels are now called "tiers". Nearly every class feature, feat, power, trait, etc. has a tier.
WILDING: The opposite of "imperial" is wildling, referring to those who live out in rural areas or wilderness. Wildling is often conflated with the word "barbarian", and is typically considered a pejorative term to refer to people as primitive.