How a company's stock price fares relative to its peers (or relevant asset group) is referred to as Relative Performance. It is also called Relative Return and is similar to Relative Strength.
For example, in 2008, Exxon Mobile (XOM) comprised 4.14% of the S&P 500 (SPY). As such we would expect Exxon Mobile's price to have a relative performace similar to the Spyders. The price performance of XOM relative to XLE would be even closer given that it currently constitutes 17.03% of that energy ETF.
Absolute performance is another term that is often encountered when reading about relative performance.