Quasidimensionless group (corrected, referred, or non-dimensional) definitions are summarised in Chart 4.2 of Source 1. Additional resource for corrected or referred speed: https://en.wikipedia.org/wiki/Corrected_speed.
Sources
1. P. P. WALSH and P. FLETCHER, Gas Turbine Performance, 2. ed., [repr.], Blackwell Science, Oxford (2004).