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
catch up on (something)
to do something that you have not had time to do, to learn about something (the daily news or news about old friends)
I need to catch up on some of my reading this weekend. I met my friend and we caught up on some news.