Leaf depth in a code tree
= Leaf depth in a code tree
{title2=$d_x=|c(x)|$}
= Leaf depths in a code tree
{synonym}
The number of <edges> on the <graph path> from the <root of a tree> to the leaf for symbol $x$ in a <code tree>. The <root of a tree> has depth zero. Each <edge> contributes one <bit> to a binary <codeword>, so this depth equals the <codeword length>; weighting these depths by <probabilities> gives <expected codeword length>.