Jot down cob's partner (3)
I believe the answer is:
pen
This clue could be a double definition.
'jot down' is the first definition.
Although both the answer and definition are verbs in their base form, I can't see how they can define each other.
'cob's partner' is the second definition.
(I've seen this in another clue)
Can you help me to learn more?
(Other definitions for pen that I've seen before include "Shut up" , "International Association of poets, playwrights etc" , "Confine the writer" , "Write" , "Writing implement" .)