| bell jar | (n) a bell-shaped glass cover used to protect and display delicate objects or to cover scientific apparatus or to contain gases, Syn. bell glass |
| Bell jar | (Phys.) A glass vessel, varying in size, open at the bottom and closed at the top like a bell, and having a knob or handle at the top for lifting it. It is used for a great variety of purposes; as, with the air pump, and for holding gases, also for keeping the dust from articles exposed to view. [ 1913 Webster ] |