Be prepared to consider appearance (11)

I believe the answer is:
countenance
'appearance' is the definition.
(countenance is a kind of appearance)
'be prepared to consider' is the wordplay.
I cannot really understand how this works, but
'be' could be 'count' (counting is a kind of being) and 'count' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for countenance that I've seen before include "A person's face; admit as possible" , "Favour" , "Accept as possible; face" , "brook" , "features" .)
