详细解释:n. 先行, 优先
【化】 进动; 旋进
词型变化：
形容词:precessional英语解释：
名词 precession:
the motion of a spinning body (as a top) in which it wobbles so that the axis of rotation sweeps out a conethe act of preceding in time or order or rank (as in a ceremony)同义词：precedence, precedency