Friction coefficient in turbulent shear flows over smooth surfaces depends on flow Reynolds number.  Traditionally, the freestream(bulk) velocity (U_∞ or U_b) in boundary layers(pipes/channels), which is technically a boundary condition (BC), is taken to be the velocity scale for rendering friction velocity and flow thickness dimensionless. This approach does not lead to a universal framework across flows with different geometry, accelerations and history effects. The correct choice of velocity scale dictated by the dynamics (M -ν scaling) and a suitable empirical top-up for the effects of BCs (using Clauser’s shape factor G) unravel the universality of friction scaling. The resulting new semi-empirical dimensionless framework (M -ν-G scaling) collapses friction data from a vast variety of flows on to a universal curve and this curve can be modeled using a single equation with predictive power. The talk discusses these findings and also their possible application to model surface layer fluxes in near-neutral and convective atmospheric boundary layers.