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