A post is a role, or a set of roles, which is officially assigned in a specific collective.
Most posts are based on one specific role; however, they often authorize several sub-roles which are intended to facilitate effective performance of the basic role. For example, a committee chairperson could have a set of many official powers which are automatically authorized by the chairperson post. Such sets of official powers, while common, are often unstable, and are frequently modified as collectives develop.
A post often identifies a role which is uniquely assigned within a specific collective. However, a post can also define a team.
Position and title are often used as synonyms of post. However, those terms have other uses which are more fundamentally useful in modular organization. Therefore, they are used differently in Modular Organizing Terminology.