Assertion: headphone | /r/IsA | one of four main types
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Headphones come in many varieties, but are usually classified as one of four main types: circumaural (around the ear), supra-aural (cushioned against the ear), earbud (partially inserted into the ear canal) and in-ear (fully inserted into the ear canal.)