1. Achievement of full development or growth.
2. Developmental changes that lead to maturity.
3. Processing of a macromolecule, posttranscriptional modification of RNA or posttranslational modification of proteins.
4. The overall process leading to the incorporation of a viral genome into a capsid and the development of a complete virion.
The definition information for maturation is provided by Stedman's. You can search our medical dictionary here.