Tech stack
The specific set of languages, frameworks, databases, and hosting tools a company uses to build its product.
What it tells you about a developer
A full-stack match is a convenience. Core-language match plus evidence of learning speed predicts success better. Weight the language and the discipline, and treat the rest of the stack as learnable.
A stack description like 'TypeScript, Next.js, Postgres on AWS' names the language, the web framework, the database, and the cloud in one line. Job descriptions often compress their requirements into a stack. Candidates rarely need to match every layer of one to succeed in the role.