Meaning of DEFENSE in English
1. Any move or plan that is intended to meet or stop an enemy's threats or attack.
2. Name used for openings initiated by black, such as Petroff Defense, French Defense. etc. These systems are called defenses due to black having the second move, and being forced to respond to white's first move.
English glossary of chess terms. Английский глоссарий шахматных терминов. 2012