无圈有向图, 非循环有向图的英文

acyclic digraph

• 无:    not have; there is ...
• 圈:    circle; ring
• 有:    5年 fifteen years
• 向:    direction
• 图:    picture; chart; dr ...
• 非:    mistake; wrong; er ...
• 循环:    circulate; circle; ...