Because when bones (of a dead creature) are left out or buried the flesh on them eventually disappears and they become very dry.
This means very dry/thirsty Give me a drink I'm as dry as a bone! Look at this firewood it's as dry as a bone.
Dry As a Bone was created in 1987-07.
It is two words: bone dry.
As dry as a bone.
Yes, running an engine with out oil will damage it.
its as dry as bones
Similes for dry: As dry as a scorching desert. Dry as a bone. Dry as the Sahara.
The cast of Bone Dry - 2011 includes: Laura Grey Jordan Klepper
The cast of Bone Dry Blues - 1922 includes: Billy Ruge
When you see "As ___ as ____" you are looking at a simile, not an idiom. A simile is just a way of comparing two things in a vivid way. In this case, you're comparing something to a dry, hard bone. In other words, this thing is very dry.
The lyrics were, "Your leg bone connected to your knee bone".
When the cactus is dry but not bone dry. Do not over water it.