The Collaborative International Dictionary of English v.0.48:

Cairo \Cairo\ prop. n. (Geography)
   The capital city of Egypt. It is the largest city in Africa.
   Population (2000) = 7,010,000.

   Syn: El Qahira, Egyptian capital, capital of Egypt.
        [WordNet 1.5 +PJC] cairngorm

WordNet (r) 3.0 (2006):

Cairo
    n 1: a town at the southern tip of Illinois at the confluence of
         the Ohio and Mississippi Rivers
    2: the capital of Egypt and the largest city in Africa; a major
       port just to the south of the Nile delta; formerly the home
       of the Pharaohs [syn: Cairo, Al Qahira, El Qahira,
       Egyptian capital, capital of Egypt]

The Free On-line Dictionary of Computing (19 January 2023):

Windows NT 4
Cairo

    A version of Microsoft's Windows NT
   operating system, originally code named "Cairo".  It was
   supposed to ship in the first half of 1995.  Details are
   scarce, but it is intended to provide an object-oriented
   version of Windows.

   (1996-07-09)