In a primary metaphor, the concept which serves to structure a primary target concept. Primary source concepts are relatively simple aspects of sensory experience, such as motion, vertical elevation, proximity, hunger, warmth, etc.

They are held to constitute redescriptions of specific aspects of sensory experience and are correlated with subjective evaluations and responses (primary target concepts). Accordingly they are held to be comprised of what is referred to as 'image content', which relates to the idea that primary source concepts derive from sense-perception of the external world.