subdominant
Harmony that pulls away from home and sets up tension (the IV side).
The chord a fourth above home (IV in a major key), and the gentler of the two tension-makers. It leans away from the tonic and often sets up the dominant, as in the everyday IV to V to I. Softer than the dominant, it colors and departs rather than demands.
Learn it: Roman numerals
The one-sentence definition at the top is the same one the Theory Aide extension shows as a tooltip inside Ableton Live. Hover any dotted term for its own.