Good semantic research! :thumbs:Even now, the word bottle is still used of non-rigid vessels, not "made of a solid material like glass":
water bottle:
http://www.walgreens.com/store/c/walgreens-water-bottle/ID=prod17205-product
collapsible hydration bottle:
http://www.ultralightdesigns.com/products/hydration/evernew2000.html