Also found in: Acronyms, Wikipedia.
X1(1) A cable TV entertainment operating system from Comcast. Introduced in 2012, the Xfinity X1 platform lets people use tablets and smartphones as an auxiliary interface. See Xfinity.
(2) (Times 1) x1 may refer to a PCI Express (PCIe) interface with a single lane. See PCI Express.
(3) A desktop search program for Windows from X1 Technologies, Inc., Pasadena, CA (www.x1.com) that includes a file viewer for more than 225 formats. Introduced in 2004, X1 provides search capabilities for Office documents, various email messages, as well as PDF and ZIP files. See desktop search.