third force
noun
in sing.
1- a political group or party acting as a check on conflict between two extreme or opposing groups第三种力量, 中间势力（指在两种极端或相互抗衡的力量之间起抑制作用的政治团体或党派）。
1.1
- (in South Africa) a supposed group thought by some to have carried out acts of violence to incriminate members of left-wing groups representing blacks, and so sow discord among these groups（南非）第三团体（据认为此团体从事暴力活动, 并将其归咎为是代表黑人的左翼团体成员所为, 从而在各团体间制造冲突）。