The Collaborative International Dictionary of English v.0.48:

Fossil \Fos"sil\, n.
   1. A substance dug from the earth. [Obs.]
      [1913 Webster]

   Note: Formerly all minerals were called fossils, but the word
         is now restricted to express the remains of animals and
         plants found buried in the earth. --Ure.
         [1913 Webster]

   2. (Paleon.) The remains of an animal or plant found in
      stratified rocks. Most fossils belong to extinct species,
      but many of the later ones belong to species still living.
      [1913 Webster]

   3. A person whose views and opinions are extremely
      antiquated; one whose sympathies are with a former time
      rather than with the present. [Colloq.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fossil \Fos"sil\, a. [L. fossilis, fr. fodere to dig: cf. F.
   fossile. See Fosse.]
   1. Dug out of the earth; as, fossil coal; fossil salt.
      [1913 Webster]

   2. preserved from a previous geological age; as, fossil water
      from deep wells; -- usually implying that the object so
      described has had its substance modified by long residence
      in the ground, but also used (as with fossil water) in
      cases where chemical composition is not altered.
      [PJC]

   3. (Paleon.) Like or pertaining to fossils; contained in
      rocks, whether petrified or not; as, fossil plants,
      shells.
      [1913 Webster]

   Fossil copal, a resinous substance, first found in the blue
      clay at Highgate, near London, and apparently a vegetable
      resin, partly changed by remaining in the earth.

   Fossil cork, Fossil flax, Fossil paper, or Fossil
   wood, varieties of amianthus.

   Fossil farina, a soft carbonate of lime.

   Fossil ore, fossiliferous red hematite. --Raymond.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fossil
    adj 1: characteristic of a fossil
    n 1: someone whose style is out of fashion [syn: dodo, fogy,
         fogey, fossil]
    2: the remains (or an impression) of a plant or animal that
       existed in a past geological age and that has been excavated
       from the soil

Moby Thesaurus II by Grady Ward, 1.0:

99 Moby Thesaurus words for "fossil":
   Methuselah, afterglow, afterimage, ancient manuscript,
   antediluvian, antique, antiquity, archaism, artifact, back number,
   balance, butt, butt end, candle ends, cave painting, chaff,
   conservative, dad, debris, detritus, dodo, elder, end, eolith,
   fag end, filings, fogy, fud, fuddy-duddy, granny, has-been,
   holdover, husks, leavings, leftovers, longhair, matriarch,
   mezzolith, microlith, mid-Victorian, mossback, neolith,
   odds and ends, offscourings, old believer, old crock, old dodo,
   old fogy, old liner, old man, old poop, old woman, old-timer, orts,
   paleolith, parings, patriarch, petrification, petrified forest,
   petrified wood, petroglyph, plateaulith, pop, pops, rags,
   reactionary, refuse, regular old fogy, relic, relics, reliquiae,
   remainder, remains, remnant, residue, residuum, rest, roach,
   rubbish, ruin, ruins, rump, sawdust, scourings, scraps, shadow,
   shavings, square, starets, stick-in-the-mud, straw, stubble, stump,
   survival, sweepings, trace, traditionalist, vestige, waste



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

FOSSIL
       Fido Opus Seadog Standard Interface Layer


The Jargon File (version 4.4.7, 29 Dec 2003):

fossil
 n.

    1. In software, a misfeature that becomes understandable only in historical
    context, as a remnant of times past retained so as not to break
    compatibility. Example: the retention of octal as default base for string
    escapes in C, in spite of the better match of hexadecimal to ASCII and
    modern byte-addressable architectures. See dusty deck.

    2. More restrictively, a feature with past but no present utility. Example:
    the force-all-caps (LCASE) bits in the V7 and BSD Unix tty driver,
    designed for use with monocase terminals. (In a perversion of the usual
    backward-compatibility goal, this functionality has actually been expanded
    and renamed in some later USG Unix releases as the IUCLC and OLCUC bits.)


The Free On-line Dictionary of Computing (30 December 2018):

fossil

   1. In software, a misfeature that becomes understandable only
   in historical context, as a remnant of times past retained so
   as not to break compatibility.  Example: the retention of
   octal as default base for string escapes in C, in spite of
   the better match of hexadecimal to ASCII and modern
   byte-addressable architectures.  See dusty deck.

   2. More restrictively, a feature with past but no present
   utility.  Example: the force-all-caps (LCASE) bits in the V7
   and BSD Unix tty driver, designed for use with monocase
   terminals.  (In a perversion of the usual
   backward-compatibility goal, this functionality has actually
   been expanded and renamed in some later USG Unix releases as
   the IUCLC and OLCUC bits.)

   3. The FOSSIL (Fido/Opus/Seadog Standard Interface Level)
   driver specification for serial-port access to replace the
   brain-dead routines in the IBM PC ROMs.  Fossils are used by
   most MS-DOS BBS software in preference to the "supported"
   ROM routines, which do not support interrupt-driven operation
   or setting speeds above 9600; the use of a semistandard FOSSIL
   library is preferable to the bare metal serial port
   programming otherwise required.  Since the FOSSIL
   specification allows additional functionality to be hooked in,
   drivers that use the hook but do not provide serial-port
   access themselves are named with a modifier, as in "video
   fossil".

   [Jargon File]


U.S. Gazetteer Places (2000):

Fossil, OR -- U.S. city in Oregon
   Population (2000):    469
   Housing Units (2000): 245
   Land area (2000):     0.763277 sq. miles (1.976878 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.763277 sq. miles (1.976878 sq. km)
   FIPS code:            26650
   Located within:       Oregon (OR), FIPS 41
   Location:             44.999595 N, 120.214239 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Fossil, OR
    Fossil