Value is a relative label based on multiples such as pe-ratio and price-to-book. The category includes genuinely mispriced companies and value traps, which are cheap because the business is shrinking. Distinguishing them is the entire job.
Value and growth-stock leadership alternate in long regimes, often tied to interest rates, which is why style performance is usually measured over years rather than quarters.
Example: a stock at $30 earning $5 has a P/E of 6 against a market at 20. If earnings hold and the multiple moves to 9, the stock is $45. If earnings fall to $2 and the multiple stays at 6, it is $12.
Related: growth-stock, pe-ratio, price-to-book, dividend-yield