MRPG Buffs and Modifiers
A "buff" is any item/spell/potion/ability/etc that increases, decreases, or otherwise changes a skill, stat, or proficiency. Most buffs add to the total "buffed" score for an item, but there are exceptions. Potions, for example, actually raise base stats(so an Intelligence-enhancing potion raises your base (unbuffed) Intelligence temporarily.
The term "buffed" applies to the total score after all buffs are applied.
Example: a character has a base STR of 10 and is wearing a Ring of Strength +2, their base STR is still 10, but they have a buffed STR of 12.
Buffed stats apply to proficiency caps. If a player has 12 points in a Weapon Proficiency, but only 10 strength, they would recieve only 10 points of the proficiency, but if they buffed the strength to 12, they would get all 12.