Cannabidiol (CBD) is a naturally occurring constituent of industrial hemp/cannabis. It is the most abundant non-psychoactive cannabinoid found in cannabis, and is being scientifically investigated for various reasons.
CBD oil is a cannabis oil (whether derived from marijuana or industrial hemp, as the word cannabis is the Latin genus name for both) that has significant amounts of cannabidiol (CBD) contained within it. CBD oil is derived from industrial hemp, also often called CBD-rich hemp oil, hemp derived CBD oil, CBD-rich cannabis oil, or plainly “hemp extracts” since it typically contains much more than just CBD. Again, cannabis doesn’t mean marijuana, but is the genus name, and general umbrella term which all forms of marijuana and hemp fall under.