焉, originally bird, is used as a modal particle with meanings: thereupon, then; how? why? where? It serves as phonetic component to form characters. Most of the characters formed by the phonetic component 焉 have the same pronunciation as that of 焉.
Characters with the phonetic component 焉
嫣 鄢 傿 墕 漹 篶 with the same pronunciation yān
Further study of 焉