Speed
noun
Your fastness degree is your speed.
You use 速度 to talk about a specific speed of something like a car or a train. If you want to talk about speed more casually, you can just say スピード or 速さ.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
インターネットの速度がおそすぎてイライラしています。
These internet speeds are too slow and it’s pissing me off.
もう少し速度を下げて走行してください。
Lower the speed a little more, please.
姉は朝ごはんの食パンを口に入れたまま、すごい速度で学校に走っていきました。
My older sister ran to school at such an incredible speed, with bread in her mouth.