Rhesus factor or Rh factor, see Blood type

Reinhard Heydrich

The anime Rumbling Hearts

The Riemann hypothesis, an important unsolved problem for mathematics.

Rhodium, a chemical element

Ryan's Hope, a soap opera

Red Hat GNU/Linux operating system

Relative humidity

Reading Horizons, a phonics based reading program based off of the Discover Intensive Phonics for Yourself methodology

Rh (digraph)

Royal Highness

The RH postal area in the United Kingdom Royal Mail postcode system

Republic Express Airlines, IATA airline designator

Rhesus factor, a classification to describe blood types in humans, and a related disease of newborns

Right hand or Right-handed