| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
| a calculus or concretion found in the stomach or intestines of certain animals, esp. ruminants, formerly reputed to be an effective remedy for poison. |
A much used expression that has lost its freshness and descriptive power. Some clichés are “I thank you from the bottom of my heart” and “It's only a drop in the bucket.”