Is 'sinus' a countable noun?

Yes, in anatomy (e.g., 'the frontal sinuses'), but often treated as uncountable when referring to the medical condition (e.g., 'I have sinus').

What's the difference between 'sinus' and 'sinusitis'?

'Sinus' is the anatomical cavity. 'Sinusitis' is the medical condition meaning inflammation or infection of the sinuses.

Can 'sinus' be used as a verb?

No, 'sinus' is only a noun. There is no verb form.

Is the pronunciation different in British and American English?

No, both pronounce it /ˈsaɪ.nəs/.

Is “sinus” formal?

Sinus is usually technical/medical/scientific in register.

How do you pronounce “sinus”?

Sinus: in British English it is pronounced /ˈsaɪ.nəs/, and in American English it is pronounced /ˈsaɪ.nəs/. Tap the audio buttons above to hear it.

sinus: meaning, definition, pronunciation and examples

UK/ˈsaɪ.nəs/US/ˈsaɪ.nəs/

Technical/Medical/Scientific

My Flashcards

Quick answer

What does “sinus” mean?

a cavity, hollow space, or channel.

Audio

Pronunciation

Definition

Meaning and Definition

a cavity, hollow space, or channel; in anatomy, a hollow space in bone or other tissue

In mathematics, refers to the sine function; in medicine, refers to sinusitis or sinus infections; also used in other scientific contexts for cavity-like structures (e.g., cardiac sinus)

Dialectal Variation

British vs American Usage

Differences

No significant differences in meaning or usage; both use primarily in medical/scientific contexts.

Connotations

Identical medical/scientific connotations in both varieties.

Frequency

Slightly more frequent in American English due to higher incidence of allergy/sinus condition advertisements.

Grammar

How to Use “sinus” in a Sentence

suffer from (a) sinus (infection)have (a) sinus (problem)treat (a) sinus (condition)the sinus of (an angle)

Vocabulary

Collocations

strong

sinus infectionsinus headachesinus pressuresinus cavityparanasal sinus

medium

chronic sinusblocked sinussinus troublesinus painsinus surgery

weak

sinus reliefclear sinusdrain sinusinflamed sinus

Examples

Examples of “sinus” in a Sentence

adjective

British English

sinus problems
sinus medication

American English

sinus issues
sinus medicine

Usage

Meaning in Context

Business

Rare; might appear in pharmaceutical/healthcare marketing.

Academic

Common in medical, anatomical, mathematical, and engineering texts.

Everyday

Used mainly in health contexts (e.g., 'I have a sinus infection').

Technical

Standard term in anatomy, medicine, mathematics (sine function), and engineering.

Vocabulary

Synonyms of “sinus”

Strong

antrumair cavity

Neutral

cavity hollow passage

Weak

channel duct

Vocabulary

Antonyms of “sinus”

solid mass tumor

Watch out

Common Mistakes When Using “sinus”

Using 'sinus' as a countable noun without article when referring to the condition (e.g., 'I have sinus' instead of 'I have a sinus infection').
Confusing 'sinus' (noun) with 'sinusitis' (medical condition).

FAQ

Frequently Asked Questions

: Yes, in anatomy (e.g., 'the frontal sinuses'), but often treated as uncountable when referring to the medical condition (e.g., 'I have sinus').
: 'Sinus' is the anatomical cavity. 'Sinusitis' is the medical condition meaning inflammation or infection of the sinuses.
: No, 'sinus' is only a noun. There is no verb form.
: No, both pronounce it /ˈsaɪ.nəs/.
: a cavity, hollow space, or channel.
: Sinus is usually technical/medical/scientific in register.
: Sinus: in British English it is pronounced /ˈsaɪ.nəs/, and in American English it is pronounced /ˈsaɪ.nəs/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

“No common idioms”

Learning

Memory Aids

Mnemonic

SINus is INSide your head (cavities inside the skull).

Conceptual Metaphor

CONTAINER (for air, mucus, infection)

Practice

Quiz

Fill in the gap

The of 90 degrees equals one.

Multiple Choice

In which field is the word 'sinus' LEAST likely to be used?