# What does the word Entropy refer to in Entropy encoding

I have come know of Huffman and Arithmatic encoding that try to curtail redundant data and thus compress data. Why are they called Entropy encoding? What does that mean? Why not just call them compression encoding?

A perfect, lossless compression scheme could theoretically reduce the number of bits of a message to $ceil(log_2(entropy))$ but no further. Lossy compression schemes can reduce further, but information will be lost.