Postcard
noun
A writing that you put on a leaf is like something else. Instead of a leaf, think about writing you put on a leafish sized item. A postcard perhaps?
The reading is kind of weird, sorry. The reading for 葉 is the は you know and love. Then, 書 is かき despite not having a き on the end like you'd expect. So, it's weird. It's shortened like a postcard is a shortened letter, I suppose? Technically it is the 書き reading, but keep in mind that 書き gets rendaku'd.
ちょっとその葉書をお借りしてもいいですか？
Could I borrow the postcard for a moment?
ゆう便局で葉書を買ったんだけど、お金をはらったあと、そのまま忘れてそこにおいてきちゃったみたい。
I bought postcards at the post office, but it seems that I left them there after paying.
コウイチが実はとある秘密の国の王子様で、のっぴきならない理由のためポートランドオレゴンで身分を隠してトーフグの社長として生きているという奇妙な葉書を受け取った。
I received a weird postcard saying that Koichi is actually the prince of a secret country, but he is living incognito as the Tofugu president in Portland, Oregon for some unavoidable reason.