鄢 is met today as a surname and in old place names. 鄢陵 in Henan was the site of a major battle in 575 BCE between the states of Jin and Chu, one of the turning points of the Spring and Autumn period.
The right-side 'city' radical, a compressed form of 邑 (town). On the right it always means a settlement or place name - exactly why 鄢 names a district, alongside 都 and 邦.
Supplies the sound. Standalone 焉 is a classical word meaning 'where' or 'how'; here it gives the exact yān reading and carries no meaning into the place name 鄢.
