Form of halter sometimes seen on a horse (6)

I believe the answer is:

lather

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

'sometimes seen on a horse' is the definition.
I can't judge whether this defines the answer.

'form of halter' is the wordplay.
'form of' indicates anagramming the letters (the letters need to be in another 'form').
'halter' with letters rearranged gives 'LATHER'.

Can you help me to learn more?

(Other definitions for lather that I've seen before include "Turner" , "Panic" , "Soapy froth" , "Agitated state" , "Whip up froth - tizzy" .)

I've seen this clue in the Evening Standard.

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.