High Voltage Glossary

The High Voltage glossary at

http://www.highvoltageinfo.com/glossary.php provides definitions for
such terms as corona, dielectric withstanding voltage and creepage
distance. Other terms with particular meanings for high voltage
applications include:

FLASHOVER (A disruptive discharge of electricity through an
insulator, normally characterized by a voltage drop. Also, a
discharge around or over a liquid or solid material. This can be a
single event, intermittent or continuous. Same as Arc)

TRACKING (Marks made on a surface that experienced flashover)

CORONA INCEPTION VOLTAGE: The lowest voltage at which continuous
corona of specified pulse amplitude occurs as the applied voltage is
gradually increased.