The Threshold Between Two Domains
A cusp is a boundary degree either between two houses or between two zodiac signs. The house cusp is the degree at which one house ends and the next begins. The sign cusp is the 0° of any sign the degree at which the Sun transitions from one sign to the next (e.g., 0° Aries is the cusp between Pisces and Aries). Planets within 2–3° of a house cusp are considered to have influence in both houses; planets exactly on the cusp are fully read in the house they are entering.
Cusps in Practice
| Type | Meaning |
|---|---|
| Angular house cusps (1,4,7,10) | Most powerful life direction markers |
| Sign cusp (0° of any sign) | Strongest expression of sign's new energy |
| Planet near a cusp | Influence in adjacent houses; check both |
The Sign Cusp and "Cusp Babies"
Popularly, "born on the cusp" refers to people born when the Sun is near a sign boundary but this is a misnomer astrologically. The Sun is always in one sign, never between two. A person born on the day the Sun moves from Scorpio to Sagittarius is either a Scorpio or a Sagittarius, depending on the exact birth time. The cusp myth persists because people born at the boundary may absorb qualities of the adjacent sign through other chart factors but the Sun sign itself is definite, not blended.