Intense violence, blood and gore, sexual content, and/or strong language. AO (Adults Only) Prolonged intense violence or graphic sexual content. Detailed Content Descriptors

Graphic violence, explicit sexual activity, or crude indecent language. M (Mature)

Beyond the age rating, many systems include specific "content descriptors" to explain why a program received its rating: ESRB Ratings Guides, Categories, Content Descriptors

Intense violence, hard language, sexual nudity, or drug abuse. NC-17 Explicit adult content more intense than an R rating. TV Shows TV-MA