n.
1.a correlation between two variables (e.g., between the number of electric motors in the home and grades at school) that does not result from any direct relation between them (buying electric motors will not raise grades) but from their relation to other variables
Idiom of the Day
feather one's nest
to enrich oneself (while holding public office or a trusted job etc.)
The mayor has been feathering his nest for many years and is now very rich.