acrophonic
/æk.rə.ˈfɒ.nɪk/Definitions
1. adjective
Relating to or denoting a system of writing in which each symbol represents a sound rather than an object or concept.
“The ancient Mesopotamians developed an acrophonic writing system that simplified the process of learning to read.”
2. noun
A symbol or character in an acrophonic system.
“In the acrophonic alphabet used by the ancient Greeks, each letter was a combination of two or more symbols.”