FFI

FFI (countable and uncountable, plural FFIs)

1. (uncountable) Initialism of fatal familial insomnia.
   • 2017, Matthew Walker, Why We Sleep, Penguin, published 2018, page 255:

     The underlying cause of FFI is increasingly well understood, and builds on much of what we have discussed regarding the normal mechanisms of sleep generation.

2. (countable, computing) Initialism of foreign function interface.

• FIF, Fif., IFF, iff