The Collaborative International Dictionary of English v.0.48:

Ir \Ir\ n. (Chem.)
   The chemical symbol for iridium, a metallic element of the
   platinum group. It has atomic number 77 and an atomic weight
   of 192.22.

   Syn: iridium.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Ir- \Ir-\
   A form of the prefix in-. See In-.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Ir
    n 1: a heavy brittle metallic element of the platinum group;
         used in alloys; occurs in natural alloys with platinum or
         osmium [syn: iridium, Ir, atomic number 77]
    2: a board of the British government that administers and
       collects major direct taxes [syn: Inland Revenue, IR]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

IR
       Information Retrieval


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

IR
       Internet Registry


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

IR
       Interface Repository (ORB)


The Free On-line Dictionary of Computing (30 December 2018):

IR

   1.  Internet Registry.

   2.  infrared.

   (1997-01-30)


The Free On-line Dictionary of Computing (30 December 2018):

ir

    The country code for Iran.

   (1999-01-27)


Hitchcock's Bible Names Dictionary (late 1800's):

Ir, watchman; city; vision