Distinction between two dozens

• Clock-setting button, and the theme of the puzzle
• Digital clock setting choice
• Setting on a digital clock
• Clock radio toggle
• Choice when setting an alarm
• 12-hour toggle on clocks
• Red indication on a clock radio
• Letters about time
• Clock radio letters

Wikipedia Word definitions in Wikipedia
thumb|right|upright=1.0|A BP with an ampm in Cranberry Township, Pennsylvania near Pittsburgh right off the Pennsylvania Turnpike . The ampm brand (rarely "am/pm") is a convenience store chain with branches located in several U.S. states, including Arizona ...