why is 剃刀 read as kamisori?


I just started learning kanji so I might be missing something very basic.

[剃刀](https://en.wiktionary.org/wiki/%E5%89%83%E5%88%80) =
[剃](https://en.wiktionary.org/wiki/%E5%89%83#Japanese) +
[刀](https://en.wiktionary.org/wiki/%E5%88%80#Japanese)

How come I can't combine 剃 and 刀's readings to form kamisori?




A word combined of two kanjis doesn't always read as those two kanjis
combined. In fact, lots of time it doesn't.

This word, written as 剃刀, it is actually "髪(kami)剃り(sori)". Because this is a
tool people use to shave their hair. It read as "shave" and "hair."

