We present a categorization of contextual constraints, and discuss their uses in embodied agent architectures. "Context" has been described as a difficult term to define, because it's: (1) used across numerous disciplines in cognitive science and computer science; (2) relative to an agent, or device; and (3) relative to the cognitive process being examined and experimented upon. As such, context is a consequence of theories about cognitive processes, not something observed. It has a theoretical role, not one of a measurable unit. We will take context to be the structured set of variable, external constraints to some (natural or artificial) cognitive process that influences the behavior of that process in the agent(s) under consideration. By reviewing the cognitive science disciplines of linguistics, psychology, knowledge representation, and human-computer interaction, we've identified contextual factors that can serve several uses among embodied cognitive architectures, such as knowledge acquisition, knowledge partitioning, and context switching.