Stats, or Statistics, are a measure of a Wayfinder's combat abilities and will likely determine how damage calculations and other abilities actually work numbers-wise. So far we have 6 confirmed stats in the game; Weapon Power, Crit Power, Crit Rating, Break Power, Max Health, and Ability Power. The stats seem to be organized by a color system. In this example Weapon Power and Crit Power are colored red, Crit Rating and Break Power are green, and Max Health and Ability Power are purple, each with some kind of symbol in that color behind the corresponding stats. What the purpose is for these groupings is currently unknown.
Weapon power is likely a fairly straightforward stat for how hard your weapon hits, and how much damage you'll do when you hit.
Crit Power is most likely a stat for how much extra damage you deal when you land a critical hit on an enemy. Crit Power doesn't seem to be a flat multiplier, instead is a fixed number, which may imply that your Crit Power is tacked onto your Weapon Power as raw damage when you score a critical hit.
Crit Rating seems most likely a stat for how often you will score critical hits when attacking. Once again, Crit Rating isn't a flat percentage like one might expect, and is instead a fixed number. How this fixed rating may translate to a percentage is currently unknown. It is also unknown if a Wayfinder unique abilities or weapon abilities that do damage can have a chance to critically hit.
Break Power currently is unknown in use.
Max Health is once again a more straightforward state, likely imparting a boost to maximum health for the Wayfinder. The idea that weapons can give you boosts to the Max Health stat ties in with the idea that any Wayfinder can perform a variety of different roles by changing their load out, including their weapon. So a very tanky Wayfinder like Wingrave could equip a weapon that gives less health stats and more damage stats to 'become' a more offensive role.
Ability Power is likely a stat for how good your Wayfinder unique abilities are, whether they do damage or give buffs and debuffs. For abilities that do damage this stat could just be tacked on as extra damage, but for abilities that don't do damage, it's unknown how this stat might translate into better buffs, debuffs, duration etc. It's also unknown whether this state may also buff weapon abilities.
While there could be stats that aren't visible in this very early stage of the game or stats that are left out of the one example we do have, it is of note that weapons shown in the trailers and gameplay clips do not show to provide any sort of 'defensive' stats to players. There is no mention of a defense stat, or even a physical defense or magical defense stat in the images we've seen so far. This could imply damage is dealt raw to a Wayfinder's health pool, however we do know from passives like Senja's Crowd Favorite that while Showboating she takes reduced damage, implying some sort of defensive stat is involved. Why a weapon may not impart such stats is still unknown.