lid 
(lĭd)
(lĭd)n.
1. A removable or hinged cover for a hollow receptacle or box.
2. An eyelid.
3. Biology A flaplike covering, such as an operculum.
4. A curb, restraint, or limit: approved a new lid on corporate spending.
5. Informal An act of concealment; a cover: told us to keep a lid on the report until the campaign was over.
6. Slang A hat.
7. Slang An ounce of marijuana.
[Middle English, from Old English hlid; see klei- in the Appendix of Indo-European roots.]