Marijuana and Hemp are both part of the Cannabis plant genus.
Cannabis is the plant genus name used to identify a type of flowering plant that includes marijuana and hemp. Marijuana and hemp are both part of the Cannabis Genus, yet they're different. Similar to how oranges and limes are both considered Citrus fruits, but look and taste differently. Marijuana plants are high in THC, the chemical compound that causes a "high". Marijuana that contains THC is typically used by adults for recreational purposes. Hemp plants are low in THC and high in Cannabidiol, or CBD. CBD doesn't result in a "high" and is used by those who enjoy the benefits of marijuana but don't want to interact with THC when it comes to reaching a sense of relaxation.