iconomatic
The use of pictographs to represent their sounds, as in English rebuses using an eye to mean I or in Chinese phonetic transcription of foreign terms into characters.
We have, so far as I am aware, no scientific term to express this manner of phonetic writing, and I propose for it therefore the adjective ikonomatic...
Where it comes from
A clipping of earlier icononomatic, from a modern combination of Ancient Greek εἰκών (eikṓn, “icon, image, likeness”) + ὄνομα (ónoma, “name”) + -ικός (-ikós, “-ic: forming adjectives”).
Adapted from the Wiktionary entry iconomatic (CC BY-SA 4.0).