p- and s-polarization question

Hi all, I'm spiros and...

I'm pretty mixed up as it concerns p- ans s- polarized light. 

I always thought that if you have e.g. a stretched film with dipoles
oriented at -let's say- y-axis then the planar polalised light which
is parralel to the dipoles or y axis is the p- and the one vertical to
y is s-polarized light.

If this is true then concidering an angle (polarizer's angle of
rotation) θ theta then p- or/and s- polarized light would be the
incident to the sample light for theta = 90 and 0 degrees (or the
reverse-its conventional). So there are also all the angles between
0-90 where we have partially p- combined with partially s-polarized
light.

Till now I seem to understand pretty well whats going on  but I keep
coming up to papers where I find polar diagrams of
absorption/absorbance intensity for p-and s- polarized light.

Since I am convinced that p-polarized light refers to an angle of 0 or
90 degrees I can't get how one can use "p-polarized light" at various
angles.

I must assume that I've got it wrong so please tip me on p-,
s-polarization.

thanks in advance,
spiros