Lore is information established about a setting, such as its locations, characters, creatures, and metaphysical rules (e.g. how magic works). Canon lore is usually presented in rulebooks and supplements, through expository text or fiction or images. Lore is the main part of a role-playing game's fluff, the evocative elements that contribute to fictional positioning (in contrast to pure game mechanics, sometimes called crunch).
Specific entities in a setting's lore may have associated rules and game mechanics (the stats of certain creatures is a simple example; another may be conditions that are applied in certain locations), but that is not always the case.
While lore can include stories that take place in the setting, it only contributes to the story told by the players at the table. The official lore is a backdrop and potential inspiration to the story of the player characters.
Gameable lore is lore that is useful to a GM and group during prep and play of a role-playing game. In 2020, the term is widely used in the SWORDDREAM community. Gameable lore can take various forms.
One such way that lore can be gameable is to describe places, characters and objects that can be incorporated directly in the game world and with which the player characters can meaningfully interact. Importantly, the entities thus incorporated must be sufficiently flexible that they can be turned into something tailored for the specific campaign they appear in, and can respond to the decisions and actions of the player characters. Metaplot is rarely gameable lore in this sense, whereas anti-canon material often is.
Gameable lore can also be information that informs the decisions of the players, whether it appears directly in the game or not. This can be at the level of inspiration as early as character creation, if the lore influences a player's decision about what sort of character they will play.
From the perspective of a game designer, writing gameable lore requires creating gaps in the lore that can be filled in or completed by the group that will play a game in your setting. This is an act of a designer intentionally alienating themself from their internal canon in order to allow alternative interpretations of canon (by gaming groups) to be just as valid. The alternative is to release something without gaps and force GMs and groups to impose their own interpretation anyway, because all play involves interpretation of some sort. 
- Category:Lore for pages on this wiki relating to the lore of published game settings