In the equation z = x² + y, x and y are the independent variables.

If the Government believes that part of the railways' salvation is to be found in ridding them of extraneous concerns, it should have had the courage either to close the railway works down as quickly as possible, or to hive them off as an entirely separate concern, ….

a self-locking nut

HIEROMANCY: Divination through various forms of sacrifice, or preparation for such, especially when performed by adepts in accordance with accepted rituals.