91 is a term that can refer to different things depending on the context:
- FasTrak : FasTrak is a technology used statewide in California to pay tolls electronically. It is the easiest and preferred way to pay tolls, and in some cases, it is the only way
- India Country Code : +91 is the country code for India. It is used when making international calls to India from another country
- 91 Express Lanes : The 91 Express Lanes are a set of express lanes that connect Orange and Riverside Counties in California
- Urban Dictionary : The term "the 91" is also used in a sexual context, referring to a sexual position similar to the 69, but with the person on top facing the opposite direction
