Crossword Genius

Promise part of hospital will get oxygen for American (4)

Ross

I believe the answer is:

word

I'm a little stuck... Click here to teach me more about this clue!

'promise' is the definition.
(as in 'I give you my word')

I can't explain the rest of the clue.

Can you help me to learn more?

(Other definitions for word that I've seen before include "See 19" , "Promise - unit of language" , "Message" , "Promise; news" , "Puzzle with solutions reading the same down as across" .)

I've seen this clue in The Telegraph.
Want a hint initially instead of a full solution? Install my app