Spouse's previous legal name (Form N400)

[rmuktader]

Part 10 of the form (Information About Your Marital History) asks for spouse's previous legal name. Is it asking about name last name change during marriage? Or is it simply asking if the spouse ever legally modified his/her name?

In my case, my spouse had changed his name when he got his citizenship. I am trying to figure out if I should put his old first name in this section.

Thanks in advance.