fs -abbr

  1. femtosecond

FS -abbr

  1. filmstrip
  2. Foreign Service

FSH -abbr

  1. follicle-stimulating hormone

FSLIC -abbr

  1. Federal Savings and Loan Insurance Corporation

FSO -abbr

  1. Foreign Service Officer

fstop ['ef-,stäp] -n

  1. a camera lens aperture setting indicated by an f-number