A head-mounted display (HMD)A head-mounted display (HMD), or headset, is a wearable devi…, or headset, is a wearable device that places screens and optics directly in front of the eyes to deliver an immersive visual experience. Designs range from simple smartphone holders to high-end standalone units.
Sources: Unity Glossary; XRSI Standard XR Definitions (XR-001)