antibiotic
antibiótico
a medicine that kills bacteria or stops them from growing; it does not work on viruses.
Example
A doctor gives an antibiotic for strep throat (bacteria) but not for the flu (a virus).
In Spanish
antibiótico — un medicamento que mata bacterias o impide que crezcan; no funciona contra los virus.
Un médico receta un antibiótico para la faringitis estreptocócica (bacterias), pero no para la gripe (un virus).