sinus.

A cavity or channel within bodily tissue or bone.

Use it for

Words that belong together

• a cranial sinus
• a venous sinus

On the page

The diagram distinguished the venous sinus from the air-filled space nearby.

They traced the channel into a cranial sinus.

Usage notes

Primary category: horror. Forms: Singular sinus; plural sinuses. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings.