SharePoint Search Managed Properties & Crawled Properties

Crawled properties are generated from crawling the content in SharePoint. When the Search starts crawling content, the search component can discover new properties in the content. To give an example a site column attached to a document library would be treated as an additional property to the document and will be considered as a crawled property by SharePoint Search.

Though the properties are crawled it doesn't mean that the properties will be available for search. Crawled properties are mapped to managed properties with different attributes. These attributes determine how the contents are shown in search results. Managed property is always mapped to one or several crawled properties, this mapping is sometime done automatically and many times by a search administrator.

Though Managed and crawled properties are not new in SharePoint 2013. In previous versions of SharePoint, whenever a new item was discovered during a crawl, users would have to manually create a new managed property, and map this to the corresponding crawled property. But In SharePoint Server 2013 these are done automatically.