Pas‧teur, Louis /pæˈstɜːʳ/
(1822–95) a French scientist who established the study of microbiology (=the study of very small living things such as bacteria), and proved that disease can be caused by germs. He is also known for studying fermentation (=the process by which substances change chemically and become filled with gas by the action of bacteria), and for inventing the process of pasteurization, as well as some vaccines (=substances that are put into people's bodies to protect them from diseases).

[TahlilGaran] Dictionary of Contemporary English ▲