GI's

Or G.I.'s,

[jee-ahyz]

noun

1. Slang.,  the GI's, diarrhea.

GIS

abbreviation

1. geographic(al) information system: a system for storing, editing, and displaying geographical information on computer

2. guaranteed income supplement

GIS

1. Abbreviation of Geographic Information System

Word History and Origins

Origin of GIS¹

1960–65, probably for GI shits; see GI, -s ³