| Webster's Online Dictionary |
| Expressions | Domain | Definition | |
| Birtley coal picker | Mining | An electric picker that distinguishes between good coal and slate by their different electrical conductivities. It is said to be more accurate than the human slate picker, who, when fatigued, may fail to remove all the impure material. (references) | |
Source: compiled by the editor from various references; see credits. | Top | ||
