CBD is short for cannabidiol. CBD is a cannabinoid derived from the industrial hemp plant. A cannabinoid is simply a molecule that mostly consists of hydrogen, carbon, and oxygen. The industrial hemp plant produces over 100 different cannabinoids and scientists are studying each one.
CBD is non psychoactive and non habit forming
THC and CBD are not the same thing. Although Full Spectrum products do contain 0.3% it still is not enough to give you the "high effect". If you wish to take a product with no THC you can get a Broad Spectrum which does not include any trace amount of THC.