Aptitude

1. n. Readiness in learning; docility; aptness.
2. n. A natural or acquired disposition or capacity for a particular purpose, or tendency to a particular action or effect; as, oil has an aptitude to burn.
3. n. A general fitness or suitableness; adaptation.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.