The following definitions comes from the Cochrane Handbook for Systematic Reviews of Interventions, Version 6.1.
"Systematic reviews seek to collate evidence that fits pre-specified eligibility criteria in order to answer a specific research question. They aim to minimize bias by using explicit, systematic methods documented in advance with a protocol." (chapter 1)
"Meta-analysis is the statistical combination of results from two or more separate studies." (chaptet 10)