The Collaborative International Dictionary of English v.0.48:

Eureka \Eu*re"ka\ [Gr. ? I have found, perfect indicative of ?
   to find.]
   The exclamation attributed to Archimedes, who is said to have
   cried out "Eureka! eureka!" (I have found it! I have found
   it!), upon suddenly discovering a method of finding out how
   much the gold of King Hiero's crown had been alloyed. Hence,
   an expression of triumph concerning a discovery.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Eureka
    n 1: an alloy of copper and nickel with high electrical
         resistance and a low temperature coefficient; used as
         resistance wire [syn: constantan, Eureka]
    2: a town in northwest California on an arm of the Pacific Ocean

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

Eureka

   A European technological development programme.


U.S. Gazetteer Counties (2000):

Eureka -- U.S. County in Nevada
   Population (2000):    1651
   Housing Units (2000): 1025
   Land area (2000):     4175.677522 sq. miles (10814.954673 sq. km)
   Water area (2000):    4.279109 sq. miles (11.082841 sq. km)
   Total area (2000):    4179.956631 sq. miles (10826.037514 sq. km)
   Located within:       Nevada (NV), FIPS 32
   Location:             40.011258 N, 116.267484 W
   Headwords:
    Eureka
    Eureka, NV
    Eureka County
    Eureka County, NV


U.S. Gazetteer Places (2000):

Eureka, MT -- U.S. town in Montana
   Population (2000):    1017
   Housing Units (2000): 494
   Land area (2000):     1.008335 sq. miles (2.611576 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.008335 sq. miles (2.611576 sq. km)
   FIPS code:            24850
   Located within:       Montana (MT), FIPS 30
   Location:             48.880265 N, 115.049325 W
   ZIP Codes (1990):     59917
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, MT
    Eureka


U.S. Gazetteer Places (2000):

Eureka, CA -- U.S. city in California
   Population (2000):    26128
   Housing Units (2000): 11637
   Land area (2000):     9.451197 sq. miles (24.478487 sq. km)
   Water area (2000):    5.001049 sq. miles (12.952657 sq. km)
   Total area (2000):    14.452246 sq. miles (37.431144 sq. km)
   FIPS code:            23042
   Located within:       California (CA), FIPS 06
   Location:             40.790022 N, 124.162752 W
   ZIP Codes (1990):     95501
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, CA
    Eureka


U.S. Gazetteer Places (2000):

Eureka, NC -- U.S. town in North Carolina
   Population (2000):    244
   Housing Units (2000): 124
   Land area (2000):     0.357008 sq. miles (0.924646 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.357008 sq. miles (0.924646 sq. km)
   FIPS code:            21960
   Located within:       North Carolina (NC), FIPS 37
   Location:             35.541699 N, 77.879121 W
   ZIP Codes (1990):     27830
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, NC
    Eureka


U.S. Gazetteer Places (2000):

Eureka, IL -- U.S. city in Illinois
   Population (2000):    4871
   Housing Units (2000): 1831
   Land area (2000):     2.690478 sq. miles (6.968306 sq. km)
   Water area (2000):    0.048032 sq. miles (0.124403 sq. km)
   Total area (2000):    2.738510 sq. miles (7.092709 sq. km)
   FIPS code:            24543
   Located within:       Illinois (IL), FIPS 17
   Location:             40.715620 N, 89.275220 W
   ZIP Codes (1990):     61530
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, IL
    Eureka


U.S. Gazetteer Places (2000):

Eureka, KS -- U.S. city in Kansas
   Population (2000):    2914
   Housing Units (2000): 1561
   Land area (2000):     1.955521 sq. miles (5.064775 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.955521 sq. miles (5.064775 sq. km)
   FIPS code:            21800
   Located within:       Kansas (KS), FIPS 20
   Location:             37.822745 N, 96.289583 W
   ZIP Codes (1990):     67045
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, KS
    Eureka


U.S. Gazetteer Places (2000):

Eureka, SD -- U.S. city in South Dakota
   Population (2000):    1101
   Housing Units (2000): 625
   Land area (2000):     0.934250 sq. miles (2.419697 sq. km)
   Water area (2000):    0.067060 sq. miles (0.173684 sq. km)
   Total area (2000):    1.001310 sq. miles (2.593381 sq. km)
   FIPS code:            20180
   Located within:       South Dakota (SD), FIPS 46
   Location:             45.769069 N, 99.621953 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, SD
    Eureka


U.S. Gazetteer Places (2000):

Eureka, TX -- U.S. city in Texas
   Population (2000):    340
   Housing Units (2000): 143
   Land area (2000):     2.318373 sq. miles (6.004559 sq. km)
   Water area (2000):    0.082888 sq. miles (0.214679 sq. km)
   Total area (2000):    2.401261 sq. miles (6.219238 sq. km)
   FIPS code:            24816
   Located within:       Texas (TX), FIPS 48
   Location:             32.012403 N, 96.292524 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, TX
    Eureka


U.S. Gazetteer Places (2000):

Eureka, UT -- U.S. city in Utah
   Population (2000):    766
   Housing Units (2000): 342
   Land area (2000):     1.469006 sq. miles (3.804709 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.469006 sq. miles (3.804709 sq. km)
   FIPS code:            24080
   Located within:       Utah (UT), FIPS 49
   Location:             39.954974 N, 112.116364 W
   ZIP Codes (1990):     84628
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, UT
    Eureka


U.S. Gazetteer Places (2000):

Eureka, MO -- U.S. city in Missouri
   Population (2000):    7676
   Housing Units (2000): 2622
   Land area (2000):     10.051548 sq. miles (26.033388 sq. km)
   Water area (2000):    0.060976 sq. miles (0.157927 sq. km)
   Total area (2000):    10.112524 sq. miles (26.191315 sq. km)
   FIPS code:            22834
   Located within:       Missouri (MO), FIPS 29
   Location:             38.502736 N, 90.645075 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Eureka, MO
    Eureka