Cryptic Explanation?

[Querty]

Could someone explain the RM in Armada PLEASE?
I presume the A is from the clue and ADA is a woman, but RM for jolly?

[scorpiojo]

Just answered for you here

http://www.theanswerbank.co.uk/Quizzes-and-Puzzles/Crosswords/Question1496458.html

[Mamyalynne]

Jolly

Noun

8. slang Brit a Royal Marine

[mallyh]

whats the clue?

[Mamyalynne]

25 across (6) A jolly woman in navy

[Querty]

Thank you all! I had added this question to someone else's chain but feared it might go unnoticed.

[Querty]

I've tried to mark Mamyalynne as the best answer but I'm directed to a page of what looks like Greek script???

[scorpiojo]

You've done ut :)

[scorpiojo]

* it

[Mamyalynne]

Oh that's kind but I didn't realise it had already been answered - thank you.

[Querty]

I really appreciate explanations as producing the right answer is not enough - I always want to understand the detail. I already knew ABS for able-bodied seaman, Jack, tar and RN. Now I know RM.