45-DEGREE LINE: A guideline used in Keynesian economics in conjunction with the consumption line (to derive saving) and the aggregate expenditures line (to identify Keynesian equilibrium). This guideline forms a 45-degree angle with both the horizontal income axis and the vertical consumption expenditure (or aggregate expenditures) axis in the Keynesian graphical analysis. Each point on the line represents equality between income and horizontal axis and consumption expenditure (or aggregate expenditures) on the vertical axis. See also | Keynesian economics | consumption line | Keynesian equilibrium | income | consumption | aggregate expenditures | saving | consumption-income relation |