GeneralAdvanced
TAM / SAM / SOM
Total / Serviceable / Serviceable-Obtainable Market
Three sizes of your market: TAM = everyone who could ever buy; SAM = the slice you can actually serve; SOM = the realistic share you can win soon.
Example
TAM ₹10,000 crore, SAM ₹1,000 crore (your region), SOM ₹50 crore (what you can capture in 3 years).