The Seven of Bells is Ether (pathways, hidden or revealed things, the big picture) related to the element Air (knowledge, concepts, logic). It may represent knowledge of an arcane nature, or hidden knowledge. It often represents secrets: one's own, secrets between friends, secrets kept by others, or the hidden secrets of the universe.
Sometimes this card an point to hidden meanings in communication, like subliminal or coded messages.
Perhaps it is a riddle or puzzle. It may also be a password, or a magic word which can open the way. It could be some piece of knowledge necessary to get from point A to point B.
The Abstract Seven of Bells is abstract Ether (experience in itself, journeying, sense of place) related to the element Air (mind, conceptualization, understanding). It represents altered states of consciousness, brought about by activities designed to cultivate them like meditation and prayer, or brought about by the use of substances acquired with or without a prescription.
It may represent present-centered meditation that results in serenity, a state of mind wherein sound ideas can emerge, and perceptions are less clouded. Alternatively, it could represent a state of mind brought about by prayer to a god or symbol of tumult, which could look quite different from serenity. It may even represent going into a trance.
Mind-altering drugs are sometimes necessary for people with mental illnesses to survive and find fulfillment in the world. Used wisely, they can serve to clear mental fog, or remove destructive behavior patterns. They can also enhance creativity by making possible ideas and trains of thought which would not have occurred without their presence.
With or without the presence of mind altering drugs, this card could represent a mental journey or a trip. Taking one's imagination for a ride, or taking a substance for a ride, exploration in the realm of subtle experiences can take people fascinating places. The Abstract Seven of Bells may also signify daydreaming.
Just remember to use caution while using any mind-altering techniques or drugs, because both are dangerous tools if misused. This card could also represent becoming distant, or losing touch with the real world. If it does not indicate an intentionally created altered state, it may represent pervasive disconnection from reality.