Minimum Viable Segment (MVS)
Definition
Minimum Viable Segment is the smallest group of customers you can serve profitably while achieving product-market fit. Narrower focus than TAM.
Extended Definition
Example: instead of targeting all e-commerce (too broad), focus on Shopify stores doing $1M-$10M annually selling physical goods in the US. This MVS is large enough to build a business but narrow enough to deeply understand needs. Benefits: clearer positioning, easier to dominate, faster word-of-mouth, better product decisions. Expand to adjacent segments after dominating MVS.