Total Addressable Market
Also called: TAM, SAM, SOM, market size
TAM is the total revenue available if a product captured 100% of its market, narrowed to serviceable and obtainable subsets. Venture investors care because the power law requires outcomes only large markets can produce. TAM is also the most inflated number in any pitch deck: the credible version is built bottom-up from customers times price, not top-down from an industry report.