Glossary of Control Engineering Terms

This glossary of commonly used control engineering technical terms contains a diverse range of definitions that reflects the many different industries and applications that control encompasses.

The mathematical nature of some control theory means that rigorous definitions are fundamental to many techniques. However, this glossary aims, where possible, to present simple and consequently less rigorous definitions, so that a quick overview can be obtained. Where appropriate, links to more rigorous definitions are included.

Please note that terms are currently grouped in alphabetical order.

This glossary is currently available to the wider control engineering community, though in the future access to it may be restricted to ACTC member companies only.

We hope you find this glossary practical, well organised, and relevant. This is by no means a complete glossary of all control engineering terms and updates will be made as required.

Please e-mail us your comments or suggestions for additional entries and corrections. Proper credit will be given for original and unique entries. Please note by submitting an entry you give up any copyright or other claim to it.


This glossary of terms is a compilation of information assembled from numerous sources, largely public domain. The main sources are:

Gerald Hearns, Alstom Power Conversion

It is requested that any use of this glossary be given appropriate acknowledgment.