Entity is the basic concept of Metacosm game engine. It is therefore extremely important to clearly identify what makes an Entity.
Therefore, since Metacosm goals include a high-playability and interactivity, almost anything in the game (Items, Creatures, Places...) is to be implemented as an Entity.
Cf Property-RFC
Characteristics describe an Entity from an objective point of view. They gather parameters that can be manipulated via a set of rules. Characteristics represent the core of the information manipulated by the framework when a world is simulated in Metacosm. Characteristic is a generic term for Description, Identity, Attributes, Capabilities and Skills.
For more details, see the Characteristics section.
Attributes define the inherent qualities of an entity. They describe Entities using Properties thus providing an objective description of an Entity. Attributes are basic descriptive elements of Entities. This description is not targeted at Players but at the simulation engine.
For more details, see the Attributes section.
Capabilities are derived Attributes. Capabilities are Properties that are calculated instead of being fixed and then modified. They are based on combinations of Attributes. They reflect an Entity's natural ability to perform certain types of actions, regardless of skills.
Implementation: a list of couples (coefficient, Property/Capability name)
For more details, see the Capabilities section.
Community is an abstract concept introduced to talk about a group of Entities. The word "community" is to be interpreted in a very general, abstract way since it doesn't imply anything else on member Entities than commonality between them.
An Entity is part of a given Community if it is influenced by the Influence defining the Community i.e. the Community exists only as long as several Entities are influenced by the same Influence. If an Entity isn't influenced anymore by a given Influence, it leaves the Community. Communities are implicit and only defined by the Influence. An Entity can be part of several different Communities.
An Influence defines a Community of similar Entities and how being part this Community "influences" Entities that belongs to it. An Influence gathers Characteristics and other game constructs that are common to the Community of Entities it defines, thus modifying Entities it influences. We use the term "influenced" when referring to game constructs that are modified ("influenced") by Influences and "influenceable" for game constructs that can be "influenced".
For more details, see the Influences section.