1. The power of retaining and recalling past experience
   "His remarkable retentiveness allowed him to quote entire books from memory";
   - memory, retention, retentivity
    
2. The property of retaining possessions that have been acquired
   "Her retentiveness of information made her an excellent student";
   - retentivity
    
3. The power of retaining liquid
   "The retentiveness of the soil helped prevent erosion";
   - retentivity, retention

Type of: acquisitiveness, faculty, impermeability, impermeableness, mental faculty, module