What is an ORB?
Relationship charts are based on the degress of difference between the position of planets in the birthchart of one person and the position of planets in the birthchart of the other person. If the difference is less than 7 degrees between a planet in one chart and the position of a planet in the other person's chart, then the planets are said to be making an 'aspect.' Aspects between planets are believed to influence relationships depending on the type of aspect (Conjunction, Sextile, Square, Trine, or Opposition), and the planets involved in the particular aspect.
For a more detailed explanation, and some examples Click Here
Why is the ORB set to 2 degrees?
It is believed that aspects within a 2 degree orb are the most significant in relationship charts. You can increase the orb if you want. This will reveal more aspects, but remember, the influence of these additional aspects will have a weaker influence than the aspects within a 2 degree orb.
When you read the report on the next page, you will see that the orb of each aspect is listed. This is to show you which aspects have a stronger influence and which have a weaker influence. The strongest influence are those aspects with a 0 degree Orb.