Here are some key terms:

Artificial Intelligence (AI) - Artificial intelligence, or AI, refers to the ability of computer systems to perform tasks that normally require human intelligence, like speech recognition, decision-making, and language translation.
Augmented Reality (AR) - Augmented Reality (AR) is a technology that overlays digital elements (including sound, video and imagery) on to a user’s view of the real world through a device such as a smartphone camera. It is often developed into apps and used on mobile devices to create new layers of interaction, fusing the digital with real-life worlds. The technology differs to virtual reality, which creates entirely immersive computer-generated environments for users to explore.
Multichannel Retailing - An approach to retail that offers customers several channels to interact with a retailer and purchase items on. However, a customer journey that starts on one channel cannot be continued on another.
Omnichannel - Omnichannel involves taking every channel that customers use and expect to find your business, and using all of them together in union to empower and allow the customer to experience the brand how they want to, on their terms.
Showrooming - The consumer practice of visiting a bricks & mortar store to view a product before buying it online e.g. due to lower price, wider selection/varieties, more convenient delivery
Single-Channel Retailing - Single-channel retailing provides customers with a single channel to research, purchase, collect and return products. A single-channel retailer might have a physical store, or they could have an eCommerce store, or maybe a mobile app, but they wouldn't have more than one of them.

Omnichannel Essentials Glossary