Petites are for shorter women, sleeves are cut shorter, pants rise is cut shorter, and everything is just cut shorter -- I beleive it's for 5 '5" and under.
Misses is usually even sized clothes (4,6,8,10,12), that's probably what the majority of adult women wear.
There's also, and I am drawing a blank on what it's called, is another variation of women's sizing (3,5,7,9,11,13) which are also misses type sizing but it's generally cut slimmer.
Women's sizes are not only plus sizes (14 on up)but in some cases it could also fit smaller sizes with women who aren't large just more amply endowed. Women's sizing generally have fuller busts.
Sizing also varies across designers. A size 8 in one designer, might fit a regular size 12, but some smaller women might not get their big toe in.
It's just one of the many pleasures of being a girl
