What is the meaning of G in G1?

Answer 1

I believe this is referring to the generations in parent crosses. You are first given two genotypes to cross. This is the parent generation. When you use a punnett square to cross the parent generation (P) you are given the possible genotypes of the first generation of offspring (G1)

Answer 2

In Photography, G1 refers to an aperture setting on a camera lens. The "G" stands for "Gelded" which means the lens lacks an aperture ring and relies on electronic control from the camera body to adjust the aperture.

Answer 3

G1 is the period during interphase in which the cells grows.