Arcak阿尔贾克arcn.弧；弧形物vi.形成电弧；按弧形轨迹行进arc-length base equation弧长方程arcs of mandibular closure下颌闭合弧arclength parameterization弧长参数arccotangent trigonometric反三角余切arc-extinguishing chamber灭弧罩arcus volaris superficialis掌浅弓arc-shape cutting machine弧形切割机床arc-extinguishing plastic灭弧性塑料arcus vensus dorsalis pedis足背静脉弓arcus parieto-occipitalis[医] 顶枕弓