A trine aspect in astrology, is where planets are 120 degrees apart from each other. This is the 360 degree circle divided by three.
Number Three Symbolism
In number symbolism, three is a number of harmony and completeness. Where the number two implied division, three reconciles that division. This is evident throughout our world. If we take any kind of conflict of two opposing forces we need to mediate between them and reach a balanced and fair compromise. This could be two people in an argument or two political parties debating an issue.
Even at the level of nature we see this expressed. We have the positive particle the proton, the negative particle the electron and the neutron which is necessary to hold the atom together. In the Bible, on the second day of creation the word good was left out. On the third day, it is the only day where it is mentioned twice!
There is certainly enough conflict in this world already, some more harmony and compromise is doubly needed. In the Tao symbol there is the constant interplay and balancing of the two forces, the Yin and the Yang. This is the essence of the trine, the reconciling of opposing forces into a beautiful balance. It is something we all try and achieve each day, to find a solution to the many opposing demands that are placed upon us.
Trine Aspect in Astrology
In astrology, when two planets are in trine with each other in the sky, so they are also in harmony in the psyche of the person born under this combination. They have a natural balance and ease and flow with regard to expressing the energies of these two planets. Things happen naturally and effortlessly around these two forces as their energies gently compliment one another.
The ease of the trine aspect is further exemplified by the fact that generally two planets in trine are in the same element. They could be both in water signs, or both in fire signs. The planets come from the same background as each other. They understand where the other one is coming from. It is possible to have planets in trine in different elements although it is less usual.
Venus & Uranus in Trine
Imagine a person is born under a trine between the planets of Venus and Uranus. Astrology states that the two forces exemplified by these planets will also exist inside the individual but as it's a trine, they will be in harmony with each other. Here the force of beauty, talent and abilites of Venus and the force of change, innovativeness of Uranus are at ease with each other.
The person will therefore have a natural ability and love for the unusual, and the revolutionary aspects of life. They may be the charming professor or the quirky but endearing computer geek or the person with an ability to pick up uncannily on all the latest trends enetering society. Whatever, they will have a talent and an ability around the energies expressed by these planets.
As you can see, the trine aspect endears people with great talents. It is much like in an adventure game where these are the abilities and atributes of the character you choose. People with many trine aspects are naturally blessed and have an ease and flow about their personality. There is less underlying tension and these people are easy to get along with and pleasant to be around. They may be socially charming and less likely to enter a conflict. They are at ease with themselves.
Now this all sounds too good to be true. Of course there is a negative side. People with many trines in their natal chart, can be so comfortable that they never get up and do anything with their lives. They many be too content for their own good. No event or drama in their personality is there to push them to great heights. They don't have to change because quite frankly why should they? Everything is fine just the way it is. Externally they may be born into money paralleling the gifts they were born into with their natures.
Fortunately there is another aspect between planets that involves tension, which pushes people to new heights and that is the square.