U-boat /ūˈbōt or (German) ooˈ/

A German submarine

• calltime
• calltimes
• call to account
• call to arms
• call to mind
• call to order
• calluna
• callunas
• call up
• call-up
• call-ups
• callus
• calluses
• call waiting
• calm
• calmant
• calmants
• calmative
• calmatives
• calm down
• calmed
• calmer
• calmest
• calmier
• calmiest