noun
: the mainspring unit in watches that have the main wheel detached from the barrel but turning as a unit with the barrel arbor to eliminate strain on the main wheel teeth if the mainspring should break — compare going barrel
noun
: the mainspring unit in watches that have the main wheel detached from the barrel but turning as a unit with the barrel arbor to eliminate strain on the main wheel teeth if the mainspring should break — compare going barrel
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012