ramrod

Từ điển Oxford Advanced Learner 8th

ram·rod [ramrod ramrods] BrE [ˈræmrɒd] NAmE [ˈræmrɑːd] noun
a long straight piece of iron used in the past to push ↑explosive into a gun
Idioms: ↑ramrod straight ▪ ↑straight as a ramrod