Written document and Written material

Written document noun - Writing that provides information (especially information of an official nature).

Written material and written document are semantically related. In some cases you can use "Written material" instead a noun phrase "Written document".

Written material noun - The work of a writer; anything expressed in letters of the alphabet (especially when considered from the point of view of style and effect).

Written document and written material are semantically related. Sometimes you can replace phrase "Written document" with "Written material", this phrases are similar.