/
ˈkɔːpʌs(ə)l/
n.
  - Biology  a minute body or cell in an organism, especially a red or white blood cell.
 - historical a minute particle regarded as the basic constituent of matter or light.
 
Derivative
- corpuscular
  
/kɔːˈpʌskjʊlə/
 adj. 
Etymology
C17: from L. corpusculum ‘small body’, dimin. of corpus.