# sinus

/ˈsaɪnəs/ (US) · /sˈaɪnəs/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/sinus
Updated: 2026-08-15

## Definition

a hollow space or pocket inside your body, especially the ones in the bones of your face near your nose.

For teachers: a cavity or hollow space within a bone or other tissue, most commonly referring to the air-filled paranasal cavities in the skull.

## Examples

- My sinuses feel very blocked because of this cold.
- Chronic sinus infections can cause significant pressure and pain behind the eyes and cheeks.
- The surgeon carefully navigated the narrow passages of the ethmoid sinus to remove the blockage and restore normal drainage for the patient.

## Usage notes

- Often used in the plural when referring to the facial cavities.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.