raincoat的基本意思是“雨衣”,是可数名词。

I hesitate to spend so much money on such a raincoat.我不太愿意花这么多钱买这样一件雨衣。
You can hang up your raincoat there.你可以把雨衣挂在那儿。
The rain has gone through my raincoat.雨水湿透了我的雨衣。
She hung out the wet raincoat on the line to dry.她把湿雨衣晾在外面的绳子上。
He took his neighbour's raincoats by mistake, so he hung them back outside.他错收了邻居家的雨衣,于是又把它们挂回原处。

她正把洗好的雨衣挂在晾衣绳上。
［误］  She was hanging her washing rain coat on the line.
［正］  She was hanging her washing raincoat on the line.
［析］  在表示“雨衣”时, raincoat不能分开写。