Discharges divisions including Royal Engineers (10)

I believe the answer is:

secretions

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

'discharges' is the definition.
The answer and definition can be both natural processes as well as being plural nouns.
Maybe they are linked in a way I don't understand?

'divisions including royal engineers' is the wordplay.
'divisions' becomes 'sections' ('section' can be a synonym of 'division').
'including' indicates putting letters inside.
'royal engineers' becomes 'RE' (abbreviation).
'sections' placed around 're' is 'SECRETIONS'.

Can you help me to learn more?

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app