I

Definitions of I
  1. noun
    the 9th letter of the Roman alphabet
    synonyms: i
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    type of:
    alphabetic character, letter, letter of the alphabet
    the conventional characters of the alphabet used to represent speech
  2. noun
    the smallest whole number or a numeral representing this number
    synonyms: 1, ace, one, single, unity
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    types:
    monad, monas
    a singular metaphysical entity from which material properties are said to derive
    singleton
    a single object (as distinguished from a pair)
    fellow, mate
    one of a pair
    type of:
    digit, figure
    one of the elements that collectively form a system of numeration
  3. noun
    a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks)
    synonyms: atomic number 53, iodin, iodine
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    types:
    iodine-131
    heavy radioactive isotope of iodine with a half-life of 8 days; used in a sodium salt to diagnose thyroid disease and to treat goiter
    iodine-125
    light radioactive isotope of iodine with a half-life of 60 days; used as a tracer in thyroid studies and as a treatment for hyperthyroidism
    type of:
    chemical element, element
    any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
    halogen
    any of five related nonmetallic elements (fluorine or chlorine or bromine or iodine or astatine) that are all monovalent and readily form negative ions
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