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.
Simile
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.
Similes for dry: As dry as a scorching desert. Dry as a bone. Dry as the Sahara.
dry
dry dusty
Dry As a Bone was created in 1987-07.
dry
No it's not. It's a simile.
It is two words: bone dry.
As dry as a bone.
its as dry as bones
its as dry as bones