The Jargon File (version 4.4.7, 29 Dec 2003):
priority interrupt
 n.
    [from the hardware term] Describes any stimulus compelling enough to yank
    one right out of hack mode. Classically used to describe being dragged
    away by an SO for immediate sex, but may also refer to more mundane
    interruptions such as a fire alarm going off in the near vicinity. Also
    called an NMI (non-maskable interrupt), especially in PC-land.
The Free On-line Dictionary of Computing (30 December 2018):
priority interrupt
    Any stimulus compelling enough to yank one right out
   of hack mode.  Classically used to describe being dragged
   away by an SO for immediate sex, but may also refer to more
   mundane interruptions such as a fire alarm going off in the
   near vicinity.  Also called an NMI (non-maskable interrupt),
   especially in PC-land.
   [Jargon File]
   (2005-02-13)