Should "hand" go in the plural in this idiom "like the back of their hand(s)"?

Grammarly corrects me to use the plural, but I doubt it.

I think it's the doubt of the same origin as "they had to make up their mind(s)."

  • 2
    Like the backs of their hands. Sep 1, 2021 at 19:20

1 Answer 1


Singular "hand", for the gender-neutral "their". This is the case when need a third-person pronoun, but don't want to use "his" or "her".

The person that we hire should know Python like the back of their hand.

(That is too casual for a job specification, it is just to illustrate the point)

But perhaps plural "hands" for plural "their".

My three children spent all summer playing in the woods. Now they know the woods like the backs of their hands.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .