rf

1. abbreviationinitialismInitialism of radio frequency.

   In our basis, we drove four selective radio frequency (rf) transitions between all four eigenstates

   2009 February 27, P. Neumann et al., “Response to Comment on "Multipartite Entanglement Among Single Spins in Diamond"”, in Science, volume 323, number 5918, →DOI

plural RFs

1. abbreviationcountableinitialismuncountableInitialism of right foot.
2. abbreviationcountableinitialismuncountableartsInitialism of rangefinder.
3. abbreviationcountableinitialismuncountablebusinessInitialism of radio frequency.
4. abbreviationcountableinitialismuncountablemedicineInitialism of rheumatoid factor.
5. abbreviationcountableinitialismslanguncountableengineeringInitialism of ratfuck (“dirty rick or act of sabotage or interference”).

   If battalion staff were involved, we generally called the insertion an RF, Romeo Foxtrot, or Rat Fuck.

   1997, Chuck Carlock, Firebirds: A Harrowing Firsthand Account of Helicopter Combat in Vietnam, Bantam, →ISBN, page 300

   1 more example

   Thinking they actually were supporting the demonstrators, I went up to them and asked why. “No, we're not supporting them. This is just an RF (short for “Rat Fuck”). We're keeping the money," they told me, laughing.

   2003, Guy T. Saperstein, Civil Warrior: Memoirs of a Civil Rights Attorney

6. abbreviationcountableinitialismuncountableball gamesInitialism of right field or right fielder.
7. abbreviationcountableuncountableimagingartsAbbreviation of radiance field.
8. abbreviationcountablerareuncountablevideo gamesAbbreviation of Rainbow Friends.

1. abbreviationinitialismInitialism of Russian Federation.

1. USaeronauticsreconnaissance fighter; an unarmed fighter modified for photo-reconnaissance (prefix)