PIE *aussiio-

Which was the meaning of PIE root *aussiio? and *aussiia ?

I find the followings entry here:

greek= aus= ear
latin= auris= ear
lituanian= ausis(meaning?), old lituanian =ausim
latvian= aus (meaning?)
old prusian= ausins ( akk. pl)
german= ohr
english= ear
swedish= öra

It seems that not just latin rothacised an intervocalic "s" but germanic
too. If so, which is the explanation for this rothacism of the "s" in
Latin and Germanic?