A physical component is replaceable if it is possible to replace (FRU or upgrade) the element with a physically different ...

A physical component is replaceable  if it is possible to replace (FRU or upgrade) the element with a physically different one.  For example, some computer systems allow the main processor chip to be upgraded to one of a higher clock rating. In this case, the processor is said to be replaceable . All removable components are inherently replaceable .