Riddle

This is needed both for courage and hardcover books.

Choose an answer

A.Backbone
B.Cover
C.Binding
D.Spine
Hint: It's a word with 5 letters, starting with "S".

Answer

Spine

Why this is the answer

"Spine" refers to a person's inner courage, or nerve, as well as the sturdy bound edge of a hardcover book.

This riddle is filed under Hard/Difficult Riddles and rated Medium.