Tendon
Sinew
noun
The kanji and the word are exactly the same. That means they share meanings as well, at least on the tendon side of things.
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you:
You get a horrible tendon injury, making it so you can't walk anymore. You're so upset that you blame it on Jesus. So, you go and sue Jesus for this tendon injury, and win in court, amazingly.
ジョギングをしてる時に足の筋を痛めちゃってさ。
I strained my leg when I was running.
今日は久々に牛筋のに込みでも作ってみますか。
I shall finally make beef tendon stew today.
ほら、肉を焼く前にちゃんと筋を切っておかなかったから焼いたら縮んじゃったでしょ？
Look, isn't it because you didn't cut the tendons before you fried it that the meat shrunk?