Encyclopedias, Almanacs, Transcripts, and Maps
- Cakras
- Cakrasamvara
- Cakravartin
- calabash gourd
- Calcarea (Calcareous Sponges)
- calcium carbide
- calcium hydrogencarbonate
- calcium sulphate
- Caldicott, Dr. Helen Mary (1938 – ) Australian Physician and Activist
- Caldwell, Lynton Keith (1913 – ) American Scholar and Environmentalist
- Calendars
- Calendars: An Overview
- Calendars: Mesoamerican Calendars
- Calendars: South American Calendars
- California Condor
- California redwood
- Callicot, John Baird (1941 – ) American Environmental Philosopher
- Calligraphy: An Overview
- Calligraphy: Chinese and Japanese Calligraphy
- Calligraphy: Hebrew Micrography