The Collaborative International Dictionary of English v.0.48:

Picnic \Pic"nic\, n. [Cf. F. piquenique. See Pick, v., and cf.
   Knickknack.]
   Formerly, an entertainment at which each person contributed
   some dish to a common table; now, an excursion or pleasure
   party in which the members partake of a collation or repast
   (usually in the open air, and from food carried by
   themselves).
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Picnic \Pic"nic\, v. i. [imp. & p. p. Picnicked; p. pr. & vb.
   n. Picnicking.]
   To go on a picnic, or pleasure excursion; to eat in public
   fashion.
   [1913 Webster]

WordNet (r) 3.0 (2006):

picnic
    n 1: a day devoted to an outdoor social gathering [syn: field
         day, outing, picnic]
    2: any undertaking that is easy to do; "marketing this product
       will be no picnic" [syn: cinch, breeze, picnic, snap,
       duck soup, child's play, pushover, walkover, piece
       of cake]
    3: any informal meal eaten outside or on an excursion
    v 1: eat alfresco, in the open air; "We picnicked near the lake
         on this gorgeous Sunday"

The Free On-line Dictionary of Computing (19 January 2023):

PEBCAK
PBCAK
PBKAC
PEBKAC
PICNIC

    (Or "PEBKAC", "PBCAK", "PBKAC") Tech support
   shorthand for "Problem (Exists) between Chair and Keyboard".

   An alternative is "PICNIC" - "Problem In Chair, Not In
   Computer".

   An acronym commonly used by helpdesk technicians to indicate
   that a problem is due to the user rather than the system.

   See also UBD.

   (2012-08-26)