TAM, or Total Available Market, is the total market demand for a product or service.
Technical Spike is a type of user story that helps you evaluate options and choose the best technical approach. In other words, picking a distinct part of the product and getting it working without worrying about how it looks or how it fits into the wider product. It's a throwaway experiment to learn and to prove that something can be done in a particular technology.
A generally non-legally binding document outlining the key terms of an investment by a fund, VC and occasionally by angel investors - such as valuation, voting rights, board seats, use of funds and restrictions.
“Traction” is evidence of having found your product-market fit. Traction can be generated before you’ve built a thing - using Smoke Tests for example - but is more commonly (and robustly) demonstrated using metrics such a sign-ups, repeat use, paid-for subscriptions and renewals.