1. Expression of hesitation
   - er, uh

Encyclopedia: Um

• catananche
• Catananche caerulea
• cataphasia
• cataphatic
• cataphatism
• cataphoresis
• cataphoretic
• cataphract
• cataphyll
• backhand stroke
• backhanded
• backhander
• backhaul
• backhoe
• backing
• backlash
• backless
• backlight
• backlighting
• backlog
• backmost
• backorder
• backpack
• backpacker
• backpacking