Source:http://linkedlifedata.com/resource/umls/id/C1555582
NCI: The first letter of a word, especially the first letter of each word in a proper name.,HL7V3.0: <p>Indicates that a name part is just an initial. Initials do not imply a trailing period since this would not work with non-Latin scripts. Initials may consist of more than one letter, e.g., "Ph." could stand for "Philippe" or "Th." for "Thomas".</p>