noun
Etymology: from the gerund of key by, v.
: the action of clearing an automatic stop in an emergency and permitting a train to pass a signal set at danger
noun
Etymology: from the gerund of key by, v.
: the action of clearing an automatic stop in an emergency and permitting a train to pass a signal set at danger
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012