hot bag

noun3

1. •
   A bag designed to generate and/or hold heat, used as a hot compress or warming device.

   • The exact effect of the fomentation may be secured by wrapping a hot bag with a moist flannel cloth . — 1904
2. •
   A bag for keeping pizza hot during delivery.

   • The latest hot bag innovation is based on the same technology that enabled the Thermos bottle to keep soup hot for generations of school children. — 2004
3. •
   Alternative form of hot bag.

   • The temperature of the hot-bag should not exceed 120°. — 1880