This is rather strange. It seems odd for an application form to ask for your mother's first name. A 'first name' is a given name, or, (in some countries) a 'Christian' name. But who cares whether your mother's first name was Maria or Ana? It doesn't matter, surely? Usually, forms ask for your mother's maiden name, which is her surname (family) name before she married. In most anglophone countries, women traditionally take their husband's surnames and give up their own surnames when they marry. If Mary Black marries Freddie White, she becomes Mary White. So when their children - Johnny or Jenny White, for example - fill in forms and are asked for their mother's maiden name, they would write 'Black'. As Bob says, this form is most likely asking for your mother's maiden name - the family name of your mother's father. Let's wait and see if any American members can confirm this.

They probably mean your mother's maiden name ie the family name she had before she married. So my mother's family name was Clark from my father but her maiden name was Page from her father. Hope this helps Bob

First name = Nombre de pila.