expression, godan verb (-ku)
uncask; open a barrel
Idiomatic expression literally meaning 'to pull out the mirror', referring to opening a sake barrel by removing the round wooden lid (mirror). Used in ceremonial contexts.
祝宴で、新郎新婦が鏡を抜いた。
At the banquet, the bride and groom opened the sake barrel.
The expression comes from the practice of removing the round wooden lid (called 鏡, 'mirror') from a sake barrel. The lid resembles a mirror, hence the name.