套在外面保護腿的那一層
最接近字面的那一種：腿上的覆蓋物，目的就是保護。
noun · B1
A pair of coverings for the legs that you pull on over your other clothes to keep your legs safe and dry, for example when you work outdoors, ride, or walk through rough ground.
護腿套褲
核心畫面
Think of one layer pulled onto each leg, on its own, without a seat or a doing the real work. What that layer is for decides which kind you are looking at: a layer that guards the leg from mud and thorns, or a layer that follows the leg so closely that it can be worn as trousers. The word is always plural, because there are always two legs.
可以想成「一條腿各自套上的一層」。那一層是用來做什麼的，決定了它是哪一種：一種是擋泥、擋水、擋刺的保護層；另一種貼得…更多收起
可以想成「一條腿各自套上的一層」。那一層是用來做什麼的，決定了它是哪一種：一種是擋泥、擋水、擋刺的保護層；另一種貼得很緊、跟著腿的形狀走，緊到可以直接當褲子穿。這個字永遠是複數，因為腿本來就有兩條，所以英文用 a pair of leggings 來數。Two branches
貼著腿的那一層
同樣是腿上的一層，只是改成有彈性、貼著腿走，於是它不再是保護層，而成了可以直接穿出門的褲子。
noun · A2
Tight trousers made of stretchy cloth that fit closely all the way down the legs. They are usually sold as women's clothing.
緊身褲；內搭褲