n.
   - a quantity of a medicine or drug taken at one time. ▸an amount of ionizing radiation received or absorbed at one time. 
- informal a quantity of something necessary but unpleasant.
- informal a venereal infection.
v.
  - administer a dose to.
- adulterate or blend (a substance) with another.
Phrase
  
    
      - like a dose of salts
 Brit. informal very fast and efficiently. 
[from the use of Epsom salts as a laxative.]
 
  Etymology
  ME: from Fr., via late L. from Gk dosis ‘gift’, from didonai ‘give’.