This is an entry in our Disneyland 101 Glossary: Disneyland Resort definitions in under 101 words, from Mouse Brief.
Omnimover is a ride system with continuously moving vehicles that can be individually rotated. The controlled rotation of the vehicles allows the ride’s designers to direct the attention of the riders to particular scenes. The omnimover system was created by Imagineers and patented in 1968. Examples of omnimovers currently in use at Disneyland Resort include those in the Haunted Mansion at Disneyland Park and The Little Mermaid – Ariel’s Undersea Adventure at Disney California Adventure Park.
Omnimover attractions typically use a conveyor-belt style boarding area. For more information on boarding procedures see: What It’s Like to Board a Ride at Disneyland