Hella is a slang term primarily used in Northern California, particularly in the San Francisco Bay Area. It means "very" or "a lot," and is often used to emphasize the intensity or quantity of something. For example, someone might say, "That concert was hella fun," to express that it was extremely enjoyable. The term has gained popularity beyond its regional roots and is often used in casual conversation among younger people. It reflects a unique aspect of California culture and has been featured in various forms of media, contributing to its spread in American English.