Stopper, Plug
Noun
せん
栓抜きが無くても瓶ビールの栓を抜く裏ワザを知っています。
If you don’t have a bottle opener, I know a trick to open a beer bottle.
The kanji and the word are exactly the same. That means they share meanings as well.
This has the same reading as the kanji you learned, meaning you know the reading!