A trine is an aspect centered on 120°, one third of a circle. A declared orb determines how close two points must be to that target.
Astrological traditions often associate trines with ease, reinforcement, or an established flow between two symbolic functions. Ease is not automatically beneficial: a familiar pattern can be underused or overused. The description is a reflective convention, not a scientifically measured effect.
State the exact angular separation and orb rather than relying only on a diagram line. Compare the 120° trine with the 90° square and 60° sextile.