(often used in compounds 常用于构成复合词 a long straight piece of wood, metal or glass 杆；竿；棒 
Extra Examplessee also lightning rodThe concrete is reinforced with steel rods. 混凝土用钢筋加固。 I finally managed to fix the curtain rods above the windows. 我终于设法把窗上的窗帘杆修好了。 After the accident she had an operation to put strengthening rods in her legs. 事故发生后，她做了一次手术，在腿上植入了加强棒。 He heated the end of the iron rod. 他加热了铁棒的末端。 a glass fibre rod 2 or 3 mm in diameter 直径为2或3毫米的玻璃纤维棒
- (also fishing rod, North American English also fishing pole)
a long wooden or plastic stick with a fishing line and hook attached, used for catching fish 钓竿： 带有钓鱼线和钓钩的长木棍或塑料棍，用于钓鱼fishing with rod and line 用鱼竿钓鱼
- (also the rod)(old-fashioned)
a stick that is used for hitting people as a punishment （责打人用的）棍棒 - (North American English, slang)
a small gun 手枪 see also dowsing rod, fuel rod, hot rod
Word Originlate Old English rodd ‘slender shoot growing on or cut from a tree’, also ‘straight stick or bundle of twigs used to inflict punishment’; probably related to Old Norse rudda ‘club’.
Idioms
make a rod for your own back
to do something that will cause problems for you in the future 自找麻烦；自讨苦吃
a rod/stick to beat somebody with
a fact, an argument, etc. that is used in order to blame or punish somebody 用以责备或惩罚某人的事实依据（或把柄等）
rule (somebody/something) with a rod of iron
to control a person or a group of people very severely 残酷统治；严厉控制