十三: thirteen; baker's dozen一: one第三;三分之一: third三分之一: one third; onethird; third三分之一的: third三分之一强: slightly more than one third by force三分之一弱: a little less than one third上三分之一: upper one third; upper third下三分之一: lower one third; lower third中三分之一: middle third远侧三分之一,末端三分之一: distal third舌后三分之一: posterior third of tongue牙颈三分之一: cervical third of a tooth不扣减三分之一: thirds off骨干近三分之一: proximal third of shaft of bone骨干远三分之一: distal third of shaft of bone骨干中三分之一: middle third of shaft of bone襟翼放下三分之一: extend one-third flaps气管上三分之一: upper third of trachea气管下三分之一: lower third of trachea气管中三分之一: middle third of trachea三分之一倍频程: thirdoctave三分之一标准砖: two-cut brick三分之一的面积: one-third of the area三分之一最大波高: one-third maximum wave