Understanding two hospital departments have with Epidemiology head (7)

I believe the answer is:

entente

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'understanding' is the definition.
(an entente is an alliance or understanding)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for entente that I've seen before include "Agreement between governments" , "Amicable agreement" , "Harmony" , "International understanding" , "Friendly agreement between states" .)

I've seen this clue in The Irish Times.

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