A sign is called intercepted when the sign on a house cusp is the sign before, and the sign on the next house cusp is the sign after, so the sign is skipped completely on the house cusps, and is completely contained in the house (for example, say your 5th house cusp is in Leo and your 6th house cusp is in Libra; Virgo is skipped over and is the intercepted sign in the 5th house). Houses can also be intercepted, and this occurs when the sign on the house and the next house cusp is the sign, so the house is completely contained in that sign (for example, say your 2nd house and 3rd house cusps are in Cancer; the 2nd house is intercepted in Cancer).
When it comes to interceptions, it’s helpful to think of the word contained. The sign or house that is intercepted is contained in the house or sign it’s intercepted, gobbled up by whatever that sign or house rules. The energy is therefore stuck, closed off, and boxed in. In the Virgo interception example, the Virgo energy is stuck, boxed in, overwhelmed by the 5th house. In the 2nd house example, the 2nd house energy is stuck, boxed in, overwhelmed by the Cancer energy.
Intercepted signs and houses are difficult to access in a positive way, and often require you to blend together the energies of the intercepted sign/house and the house/sign they’re intercepted in. There is an enormous amount of energy that’s being locked up, but once you can unlock it, there is great potential. The trouble is, the energy is hidden to you, and you can be afraid of it at times. Often, the energy manifests subconsciously, and you can see it play out in relationships and the people and situations you attract. When you work on embracing the synthesized sign and house, you can consciously manifest the energy in productive ways.
Interceptions can be further complicated when a planet is involved. If you have a planet in a sign that’s intercepted (in the Virgo example, a planet in the sign of Virgo), that planet gets caught up in the containment, and requires extra work to unlock. With a planet in an intercepted sign, the energy of that planet is often inaccessible to you, and you have to work on synthesizing the sign and house first, and then work on using the planet’s energy. It can be uncomfortable and unfamiliar at first, but can eventually be a source of power.
Where there are interceptions, there are also duplicates. When you have an intercepted house, two house cusps have the same sign on them, called a duplicate sign. These signs are stronger in your chart, played up almost too much. The tendency is to lean on those duplicate signs, but they need to be balanced with the intercepted signs that are missing and the house cusps involved to get everything working properly. So it’s a lot of work to deal with interceptions in your chart, but the energy that is available to you can be incredible.