Please help ID wood chair

I am guessing this is a rather common chair and with the crack/repair in the seat, not worth much.

But, was Grandpa's, so want it to go to a relative. How would you describe this chair?

-4 slat back?
-Oak?
-6 boards used for the seat, how would you describe that, "6 plank"?
-Flathead screws mean what?
-What era? 1930s or earlier?
-Is there a term for how the seat boards were joined? (see last 2 lightened pics)

 

Tongue and groove on the seat boards. And it does look like oak. Can't help you with any of the other questions, though.

 

Not really any particular historical style to peg to this. It is a simple oak kitchen chair in a vernacular style. It is 20th century and could have been made most any time. Most likely pre-WWII.

 

Baker's-that's it, I could not for the life of me, think of that for some reason
Brad-Thanks, that helps too!

 

Typical mass-produced, minimalistic arts and crafts style, utilitarian office- furniture. Found in many a catalog of the period. c. 1900-1920.

 

Interesting, I would never have thought this was related to the Arts and Crafts style, learning more every day. See why I am "curious" << ?

 

I can see how it could be termed as minimalistic arts and crafts or mission style with those flat back slats. However, I would just call it a utilitarian form. Flat back slats were used in chair backs long before the arts and crafts movement.