Nosebag
/ˈnəʊzbæɡ/
Definition 1 of 2
Pro Tip 1/3Animal Use
Used primarily to reference feeding horses, not other animals. 
The stable hand prepared the nosebag for the thoroughbred.
Pro Tip 2/3Not For Humans
Not used for human meals; don't confuse with the idiomatic usage. 
She laughed when I mistook her lunchbag for a nosebag.
Pro Tip 3/3Horse Accessories
Associated with horse gear and equine care. 
Besides a saddle and bridle, you'll need a nosebag for long rides.