(1) When used in reference to search engines, the ability of the search engine to return only relevant documents in the search results instead of documents that may not have relevance. Words in a search querythat have more than one meaning have a greater chance of returning results that are not relevant as the search engine can only guess what information the user is searching for. Precision often is expressed as a percentage and is measured by dividing the number of relevant documents produced in a search by the total number of resultant documents that the search query presented. For example, if 100 pages are found in a search and 85 of those pages are relevant then the search had 85% precision.
Floating-point numbers are often classified as single precision or double precision. A double-precision number uses twice as many bits as a single-precision value, so it can represent fractional quantities much more exactly.