Crossword Genius

Chemical of growing importance (9)

Ross

I believe the answer is:

saltpetre

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

'chemical' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for saltpetre that I've seen before include "Compound" , "Potassium nitrate" , "It's used as a fertilizer and explosive" , "Component of gunpowder" , "Gunpowder ingredient" .)

I've seen this clue in The Globe and Mail.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.