doc is the default file extension for all Word documents.
Office Open XML (OOXML) format was introduced with Microsoft Office 2007 and became the default format of Microsoft Word ever since. Pertaining file extensions include: .docx – Word document. .docm – Word macro-enabled document; same as docx, but may contain macros and scripts.
DOC is a document file format used by Microsoft Word, also used with most word processing software, including OpenOffice. DOC stands for DOCument file. A DOC file can contain formatted text, images, tables, graphs, charts, page formatting, and print settings.
MS Word 2007 and above versions of Microsoft Word save all their documents in DOCX file format by default. The new DOCX format is more efficient than the legacy DOCformat in many ways. The latest version of MS Word which is MS Word 2013 by default saves the documents in DOCX as well.
Office Open XML (OOXML) format was introduced with Microsoft Office 2007 and became the default format of Microsoft Word ever since. Pertaining file extensions include: .docx – Word document. .docm – Word macro-enabled document; same as docx, but may contain macros and scripts.