cg

1. C for Graphics (nVidia's Shader Language)
2. Cabri Geometry
3. Calcgames.org
4. Call Girl
5. Call Guard (GE two-way radio)
6. Campground
7. Canadian Geographic Magazine
8. Capacity Gages
9. Capital Gain (finance)
10. Carbon group
11. Card Game
12. Caregiver
13. Carlyle Group
14. Carnival Games
15. Carolina Group, Inc. (stock symbol)
16. Categorial grammar
17. Cayman Islands
18. Celera Genomics Corporation
19. Cell Group
20. Center Grove (High School)
21. Center of Gravity
22. Centigram 
23. Centigram
24. Central Glass (various locations)
25. Central Government (various locations)
26. Central of Georgia Railway
27. Centro Guía (Guatemala, religious group gathering center)
28. Ceremonial Guard
29. Certificate of Graduation
30. Certified Genealogist
31. Certified Graphologist
32. cg (newsreader)
33. Cg (programming language)
34. CG artwork
35. Chairman’s Guidance (US DoD)
36. Champion Gathering (Christianity)
37. Change Guide
38. Changing of the Guards (military ceremony)
39. Channel Guard (Ericsson/General Electric)
40. Chaos Guild
41. Chaotic Good (gaming)
42. Chappe et Gessalin
43. Character Generator
44. Charging Gateway
45. Chat Group (Dark Age of Camelot online game)
46. Chaudhary Group (worldwide)
47. Che Guevara (revolutionary)
48. Chelsea Grin (band)
49. Childish Gambino
50. Chorionic Gonadotropin
51. Christian-Gamers (gaming group)
52. Chromogranin
53. Cigna (CG)
54. Ciliary Ganglion
55. Cisgender (non-transgender)
56. Citizens Gas
57. City Graphic
58. Clan Genocide (gaming clan)
59. Classical guitar
60. Classification Guide
61. Climb Gradient (aviation)
62. Clinical Governance
63. Clinton Group Inc. (Canada)
64. Clock gating 
65. Cloud to Ground (lightning)
66. Coarse Graining
67. Coast guard
68. Coast Guard
69. Coastguard
70. Cockcroft and Gault
71. Code Geass
72. Code Geass (anime)
73. Code Generation
74. Coherency Granule 
75. Coimbra Group (est. 1985)
76. Color Guard
77. Colorado General
78. Combustion Gas
79. Command Guidance
80. Commandant-General
81. Commanding General (US DoD)
82. Common Gate (amplifier topology)
83. Common Ground (NYC)
84. Communication Gnome
85. Communications Gateway
86. Communications Group (USAF)
87. Community Games
88. Comparative Genocide
89. Comparative Government (political science)
90. Compass Group
91. Compilation Guide
92. Complementation Group
93. Complete game
94. Comptroller General
95. Computational Geometry
96. Computer Generated
97. Computer Genius
98. Computer Graphics
99. Computers and Games Conference
100. Concentration Guide
101. Conceptual Geniuses (est. 1993)
102. Conceptual Graph
103. Conformal Gauge (physics)
104. Congruency
105. Conjugate Gradient (iterative method)
106. Conjugate gradient method
107. Connecticut General
108. Connection Gateway
109. Consolidated Guidance
110. Constraint Grammar
111. Construction General (USACE)
112. Consul General
113. Consultative Group
114. Consumer Goods
115. Contact Group
116. Contact Guarding
117. Contadora Group
118. Contingency Guidance
119. Controls Group
120. Conversion Gain (electronics)
121. Cookie Grabber (gaming)
122. Cord Grip
123. Core Gameplay
124. cork grease
125. Corner Gas
126. Corner Guard (construction)
127. Corporate Governance
128. Corporate Governance
129. Correspondence Group
130. Cosmic Gate
131. County Government
132. Covergirl (cosmetics)
133. Cowgirl
134. Crabgrass (botany)
135. Crna Gora (Montenegro)
136. Cross Game
137. Crossing Guard
138. Crystal Gateway (Crystal City, Arlington, VA)
139. Cute Girl
140. Cute Guy
141. Cyanogenic Glucoside
142. Cypress Gardens
143. Democratic Republic of the Congo
144. Donald Glover
145. Guided missile 
146. Guided Missile Cruiser
147. Phosgene
148. Republic of Congo (country code, top level domain)