# What is indicated by the methyl- prefix?

Based on 1 carbon (or more accurately, based on $- C {H}_{3}$
The compound $C {H}_{4}$, carbon with four hydrogen atoms bonded to it, is known as "Methane".
If another species bonds to it via substitution of one of the hydrogen atoms, then it becomes a $- C {H}_{3}$ group, which is known as a "methyl group".