The word chakra is Sanskrit for wheel or disk and signifies one of seven basic energy centers in the body that correspond to nerve ganglia branching out from the spinal column, as well as states of consciousness, developmental stages of life, archetypal elements, body functions, colors, sounds, and much, much more. Together they form a profound formula for wholeness and a template for transformation.
You will find a delightful, short online chakra test at EclecticEnergies.com. It takes about 5 minutes to answer 4 to 5 dozen multiple-choice questions. When you click on "Results", you get a graph and percentages about whether each of your chakra is under-active, open or over-active.
Brofman Foundation for the Advancement of Healing:
These chakras, or energy centers, function as pumps or valves, regulating the flow of energy through our energy system. The functioning of the chakras reflects decisions we make concerning how we choose to respond to conditions in our life. We open and close these valves when we decide what to think, and what to feel, and through which perceptual filter we choose to experience the world around us.
The chakras are not physical. They are aspects of consciousness in the same way that the auras are aspects of consciousness. The chakras are more dense than the auras, but not as dense as the physical body. They interact with the physical body through two major vehicles, the endocrine system and the nervous system. Each of the seven chakras is associated with one of the seven endocrine glands, and also with a group of nerves called a plexus. Thus, each chakra can be associated with particular parts of the body and particular functions within the body controlled by that plexus or that endocrine gland associated with that chakra.
Here is a site dedicated to the chakras: Chakra Energy.com, complete with a chakra test where you will find surprising questions such as "Are you free from asthma as well as allergies (such are skin conditions, candida, yeast infections, etc.)?"
Chakra Energy.com is full of surprises. For example: "Everyday we stimulate our chakra centers in one way or another, for example, through the different thoughts we have or physically through our senses. Daily we energize our centers, consciously or unconsciously, through various methods." The sites then describes a series of ways in which we stimulate our chakras, starting with our thoughts, the sun, food, gems/minerals, clothing, art & color, etc.
Nice and simple graphic showing the chakras and their colors at Seven Power Centers or Chakras of the Kundalini System, reiki-for-holistic-health.com.