microprocessor
noun [ C ]
uk/ˌmaɪkrəʊˈprəʊsesər/ us/ˈmaɪkrəʊˌprɑːsesər/ IT
a small part of a computer, containing the CPU (= the part of a computer that controls all the other parts):
The first microprocessor built in 1971 had 2300 transistors.