Longman Dictionary of Contemporary English
Wiktionary
n. The branch of engineering that deals with the design, construction and operation of industrial process plants, and the physical, chemical and biological processes to create substances or energy in a useful and economic form.
WordNet
n. the branch of engineering that is concerned with the design and construction and operation of the plants and machinery used in industrial chemical processes
the activity of applying chemistry to the solution of practical problems
Wikipedia
Chemical engineering is a branch of engineering that applies physical sciences ( physics and chemistry) and life sciences ( microbiology and biochemistry) together with applied mathematics and economics to produce, transform, transport, and properly use chemicals, materials and energy. Essentially, chemical engineers design large-scale processes that convert chemicals, raw materials, living cells, microorganisms and energy into useful forms and products.