Shawl.
They can be even bigger, covering from the neck to the
waist.
Those that can cover from neck to knees/ankles, I think we can
safely call them Sarongs.
They are the easiest item to accessorise any outfit, even jeans
and a scruffy polo tee wearer like myself have a collection of
pashimina silk blend shawls and at least one in my bag when I go
out.
Scuffy polo tee, cheapo jeans, a shawl draped over the upper
torso makes me look elegant enough. And it hides my big fanny
pack at my fat butt so I can look more chic.
You planning to buy one for someone?