Indica is not slang for marijuana, but one of the three species of marijuana; Sativa, Indica, and Reduralis. Sativa is more of a skinny, tall, lanky, and less yielding plant that produces a
mind high. Whereas Indica is more of a small, broad, and usually a higher yielding plant that gives you a
couchlock body high.
Rederalis isn't grown due to its small amount of THC but is sometimes crossed with other species to shorten flowering time.