Word suggestion – “empty” vs “blank”

Have a question as to what makes more sense… we have a “visual search” component which allows users to type in a category (column header) and then type in what they are looking for (e.g. First Name: John) and it would spit out the results.

We want to have an option for “null”… we are debating on “Empty” vs “Blank”. Therefore a user could select First Name: then the word “Blank” or “Empty” (e.g. First Name: Blank, First Name: Empty).

What is a better name to use? Blank or Empty? Any other suggestions? Thank you in advance.