RN

1. Registered Nurse (N American)
2. Republic of Niger (also IVR)
3. Royal Navy

Rn (chem)

Radon

• secondary schools
• secondary sexual characteristics
• secondary shut-down system
• secondary shut-down systems
• secondary smoking
• secondary surveillance radar
• second ballot
• second ballots
• second banana
• second bananas
• second best
• second-best
• Second Book of Discipline
• second chamber
• second chambers
• second childhood
• second childhoods
• second class
• second-class
• second-class citizen
• second-class citizens
• second classes
• second-class mail
• second-class post
• Second Coming