There is an angle between every two planets in the horoscope which is measured in degrees. When the angle produces a significant interaction between two or more planets, they are said to be "in aspect."  The angles which give rise to the "major aspects" are produced by dividing a circle by units

Fire The Fire Triplicity is represented by the choleric or bilious temperament, exhibiting a rash, feverish, easily-excited or impulsive nature with inflammatory and bilious affections, sudden illnesses, generally acute but usually of short duration. The fiery signs (Aries, Leo and Sagittarius)

First House The First House rules the personality, natural disposition and tendencies, self-interest and worldly outlook generally. The parts of the body represented are the head and face. Second House Financial affairs, monetary prospects, gain or loss according to the nature of the planets

Aries: Head and face Taurus:  Neck, throat and ears Gemini: Hands, arms, shoulders, collar bone, lungs, nervous system Cancer: Breasts, stomach Leo: Heart, sides, upper back Virgo: Solar plexus, bowels Libra: Kidneys, ovaries, loins, lower back Scorpio: Bladder, sex organs Sagittarius: Liver,