They both have a lot on their mind.

[Nonverbis]

Wordbuilder by Guy Wellman.

Could you tell me why mind is singular here? There are two of them. I would say "minds".

 

[emsr2d2]

"To have something on one's mind" is a set phrase. It doesn't matter how many people you're talking about. Each person has just one mind.

 

[5jj]

When people blow their noses, each person has just one nose. I'd accept mind or minds in the original.

 

[jutfrank]

I naturally prefer minds though I know a lot of people would prefer the singular.