Jeffersonian refers to several fields upon which the U.S. President

• Jeffersonian architecture
• Jeffersonian democracy
• Jeffersonian Bible
• The Democratic-Republican Party were called Jeffersonians, among many other things

In fiction:

• The Jeffersonian Institution, a fictional research institute in the US television program Bones, based on the real Smithsonian Institution

In transportation:

• The Jeffersonian