The term "HQ-Dub" in "Rangasthalam 2018 Dual Audio Hindi -HQ-Dub- Sou" refers to high-quality dubbing. This means that the Hindi version of the film features professional voice actors who have meticulously worked to match the emotions and tone of the original Telugu dialogue. High-quality dubbing ensures that the movie's emotional depth and humor are preserved, providing viewers with an immersive experience.