U A term used to define the unit of height in a rack-mounted assembly. A one-U device is 13/4″ high (44mm). A two-U device is twice as tall, etc. Share this:EmailTweetLike this:Like Loading...Related Articles: Glossary: RecordistGlossary: SMPTE curveGlossary: VHFGlossary: Aspect ratio« Back to Glossary Index