n.an oblong metal coupling with a swivel at one end and an internal thread at the other into which a threaded rod can be screwed in order to form a unit that can be adjusted for length or tension
同义词：turnbuckle
英汉双解大词典
turnbuckle/ˈtɜːnˌbʌkəl/
1.
N（名词）
an open mechanical sleeve usually having a swivel at one end and a thread at the other to enable a threaded wire or rope to be tightened 螺丝扣