1. Having the same foci

Encyclopedia: Confocal

• quartermaster
• quartermaster general
• quartern
• quarters
• quarterstaff
• quartervine
• quartet
• quartette
• quartic
• quartic polynomial
• quartile
• quarto
• quartz
• quartz battery
• quartz clock
• quartz crystal
• quartz glass
• quartz lamp
• quartz mill
• quartz oscillator
• quartzite
• quartzose
• quasar
• quash
• quasi