sill的意思

n。基石(岩床,底面)Solidifying chiefly as a minor intrusion,especially as a dike or sill,before reaching the earth's surface。Used of rocks。半深成的,浅成的在到达地球表面之前的主要作为小型岩石群固化的,尤其象岩脉或岩床的凝固用于指岩石