Ig -abbr

  1. immunoglobulin

IG -abbr

  1. inspector general

IgA [,ī-(,)jē-'ā] -n

  1. a class of immunoglobulins including antibodies found in external bodily secretions (as saliva, tears, and sweat)
  2. an antibody of the class IgA

IgE [,ī-(,)jē-'ē] -n

  1. a class of immunoglobulins including antibodies that function esp. in allergic reactions
  2. an antibody of the class IgE

IGF -abbr

  1. insulin-like growth factor

IgG [-'jē] -n

  1. a class of immunoglobulins including the most common antibodies circulating in the blood that facilitate the phagocytic destruction of microorganisms foreign to the body, that bind to and activate complement, and that are the only immunoglobulins to cross over the placenta from mother to fetus
  2. an antibody of the class IgG

ig·loo ['i-(,)glü] -n

  1. an Eskimo house usu. made of sod, wood, or stone when permanent or of blocks of snow or ice in the shape of a dome when built for temporary purposes
  2. a building or structure shaped like a dome

IgM [,ī-(,)jē-'em] -n

  1. a class of immunoglobulins of high molecular weight including the primary antibodies that are released into the blood early in the immune response to be replaced later by IgG and that are highly efficient in binding complement
  2. an antibody of the class IgM

ig·ne·ous ['ig-nē-əs] -adj

  1. of, relating to, or resembling fire : fiery
  2. relating to, resulting from, or suggestive of the intrusion or extrusion of magma or volcanic activity
  3. formed by solidification of magma
    • igneous rock

ig·nes·cent [ig-'ne-sᵊnt] -adj

  1. volatile

ig·nim·brite ['ig-nəm-,brīt] -n

  1. a hard rock formed by solidification of chiefly fine deposits of volcanic ash

ig·nis fat·u·us ['ig-nəs-'fa-chə-wəs, -'fach-wəs] -n

  1. a light that sometimes appears in the night over marshy ground and is often attributable to the combustion of gas from decomposed organic matter
  2. a deceptive goal or hope

ig·nite [ig-'nīt] -vb, n, adj

  1. to subject to fire or intense heat
  2. to render luminous by heat
  3. to set afire
  4. kindle
  5. to cause (a fuel) to burn
  6. to heat up : excite
    • oppression that ignited the hatred of the people
  7. to set in motion : spark
    • ignite a debate
  8. to catch fire
  9. to begin to glow

ig·ni·tion [ig-'ni-shən] -n

  1. : the act or action of igniting: as
  2. the starting of a fire
  3. the heating of a plasma to a temperature high enough to sustain nuclear fusion
  4. the process or means (as an electric spark) of igniting a fuel mixture
  5. a device that activates an ignition system (as in an automobile)
    • put the key in the ignition

ig·ni·tron [ig-'nī-,trän] -n

  1. a mercury-containing rectifier tube in which the arc is struck again at the beginning of each cycle by a special electrode separately energized by an auxiliary circuit

ig·no·ble [ig-'nō-bəl] -adj, n, adv

  1. of low birth or common origin : plebeian
  2. characterized by baseness, lowness, or meanness

ig·no·min·i·ous [,ig-nə-'mi-nē-əs] -adj, adv, n

  1. marked with or characterized by disgrace or shame : dishonorable
  2. deserving of shame or infamy : despicable
  3. humiliating, degrading
    • suffered an ignominious defeat

ig·no·mi·ny ['ig-nə-,mi-nē, -mə-nē also ig-'nä-mə-nē] -n

  1. deep personal humiliation and disgrace
  2. disgraceful or dishonorable conduct, quality, or action

ig·no·ra·mus [,ig-nə-'rā-məs also -'ra-] -n

  1. an utterly ignorant person : dunce

ig·no·rance ['ig-n(ə-)rən(t)s] -n

  1. the state or fact of being ignorant : lack of knowledge, education, or awareness

ig·no·rant ['ig-n(ə-)rənt] -adj, adv, n

  1. destitute of knowledge or education
    • an ignorant society
  2. lacking knowledge or comprehension of the thing specified
    • parents ignorant of modern mathematics
  3. resulting from or showing lack of knowledge or intelligence
    • ignorant errors
  4. unaware, uninformed

ig·no·ra·tio elen·chi [,ig-nə-'rä-tē-,ō-i-'leŋ-,kē] -n

  1. a fallacy in logic of supposing a point proved or disproved by an argument proving or disproving something not at issue

ig·nore [ig-'nȯr] -vt, adj, n

  1. to refuse to take notice of
  2. to reject (a bill of indictment) as ungrounded

Igo·rot [,ē-gə-'rōt] -n

  1. a member of any of several related peoples of northwestern Luzon, Philippines
  2. any of the Austronesian languages of the Igorot

Igraine [i-'grān] -n

  1. the wife of Uther and mother of King Arthur

igua·na [i-'gwä-nə] -n

  1. any of various large chiefly herbivorous usu. green or brownish tropical American lizards (family Iguanidae, the iguana family) that have a serrated dorsal crest and large dewlap
  2. any of various large lizards

iguan·odon [i-'gwä-nə-,dän] -n

  1. any of a genus ( Iguanodon) of very large herbivorous dinosaurs of the early Cretaceous

IGY -abbr

  1. International Geophysical Year