After you put a rack on that bike, you'll need a pannier, French for bike bag.
From the chron.com
My grandfather had a stall in the pannier market called Good the Confectioner.
From the thisisbristol.co.uk
For heavy loads, they also use pannier-style side bags or rear bike racks.
From the online.wsj.com
Laplander says he's working on a design for an economy pannier bag.
From the sacbee.com
One overweight English bulldog carried a twin pannier of bottles.
From the nznewsuk.co.uk
They should have clearance for mudguards and fittings for attaching pannier racks front and back.
From the thisisbristol.co.uk
He was also responsible for more humble locomotives, such as many of the pannier tank classes.
From the en.wikipedia.org
He has designed a new suit-protecting pannier for bicycles.
From the telegraph.co.uk
If you have to wear a suit for work and don't want to cycle in it, consider getting a 2WG commuter pannier.
From the thisisbristol.co.uk
More examples
Either of a pair of bags or boxes hung over the rear wheel of a vehicle (as a bicycle)
A large basket (usually one of a pair) carried by a beast of burden or on by a person
Set of small hoops used to add fullness over the hips
A pannier is a basket, bag, box, or similar container, carried in pairs either slung over the back of a beast of burden, or attached to a bicycle or motorcycle. The term derives from the Old French, from Classical Latin, word for bread basket.
Panniers or side hoops are women's undergarments worn in the eighteenth century to extend the width of the skirts at the side while leaving the front and back flat. This provided a flat panel where boldly scaled woven patterns or rich embroidery could be fully appreciated.
A large basket or bag fastened, usually in pairs, to the back of a bicycle or pack animal, or carried in pairs over the shoulders; A decorative basket for the display of flowers or fruits; One of a pair of hoops used to expand the volume of a woman's skirt to either side
(Panniers) Exaggerated gathers, possibly supported by a cage, worn over the hips with a flat front.
(Panniers) These are bags that can be attached to the sides of a bicycle, either from a rear or front rack. These bags are used to carry gear, clothes or other things in.
(Panniers) bags, often hung of a rack on a bike, which are used for carrying items on a bicycle