Explore the complexities of oceanic turbulence in this lecture on meso- to submesoscale dynamics. Delve into the intricate world of multi-scale interactions and energy transfers that play a crucial role in shaping Earth's climate. Examine the challenges of quantifying these processes and their impact on energy-consistent closure in ocean and climate models. Gain insights into the combination of analytical theories, numerical models, and observational measurements used to advance our understanding of oceanic dynamics. Part of a comprehensive program on Theoretical and Practical Perspectives in Geophysical Fluid Dynamics, this lecture contributes to a broader discussion on eddies, waves, turbulence, instabilities, and frontal dynamics in the ocean.