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Theta

2007 Schools Wikipedia Selection. Related subjects: Linguistics

       Greek alphabet
   Α α Alpha   Ν ν Nu
   Β β Beta    Ξ ξ Xi
   Γ γ Gamma   Ο ο Omicron
   Δ δ Delta   Π π Pi
   Ε ε Epsilon Ρ ρ Rho
   Ζ ζ Zeta    Σ σ ς Sigma
   Η η Eta     Τ τ Tau
   Θ θ Theta   Υ υ Upsilon
   Ι ι Iota    Φ φ Phi
   Κ κ Kappa   Χ χ Chi
   Λ λ Lambda  Ψ ψ Psi
   Μ μ Mu      Ω ω Omega
      Obsolete letters
   Ϝ ϝ Digamma Ϻ ϻ San
   Ϙ ϙ Qoppa   Ϡ ϡ Sampi
   Ϛ ϛ Stigma  Ϸ ϸ Sho

   Theta (uppercase Θ, lowercase θ) is the eighth letter of the Greek
   alphabet, derived from the Phoenician letter Teth. In the system of
   Greek numerals it has a value of 9. In Classical Greek θ represented an
   aspirated voiceless dental plosive (/tʰ/), but in Koiné and later
   dialects it became a voiceless dental fricative /θ/. In American
   English, the name of the letter is commonly pronounced [θeɪɾə]. In
   Modern Greek and British English, the name is pronounced [θiːtə].

   Letters such as the early Cyrillic letter fita (Ѳ, ѳ) developed from θ.

   In its archaic form, θ was written as:
     * a cross within a circle ( A symbol of a cross within a circle or
       Another symbol of a cross within a circle )

     * and later, as a line or point within a circle ( The symbol of a
       line within a circle or The symbol of a point within a circle ).

   According to Porphyry of Tyros, the Egyptians used an X within a circle
   as a symbol of the soul; having a value of nine, it was used as a
   symbol for Ennead. Johannes Lydus says that the Egyptians used a symbol
   for Kosmos in the form of theta, with a fiery circle representing the
   world, and a snake spanning the middle representing Agathos Daimon.

   The Egyptians also used the symbol of a point within a circle ( The
   symbol of a point within a circle , the sun disc) to represent the sun,
   which might be a possible origin of its use as the Sun's astrological
   glyph. It is worthwhile to note that θῆτα (theta) has the same
   numerical value in isopsephy as Ηλιος ( Helios): 318.

   In classical Athens, it was used as an abbreviation for the Greek
   θάνατος (thanatos, "death") and as it vaguely resembles a human skull,
   theta was used as a warning symbol of death, in the same way that skull
   and crossbones are used in modern times. It survives on potsherds used
   by Athenians when voting for the death penalty.

Symbol

   The lower-case letter θ is used as a symbol for:
     * A plane angle in geometry.
     * The voiceless dental fricative in the International Phonetic
       Alphabet, such as in the words thick or thin (but not as in the,
       which is the voiced dental fricative).
     * The Potential temperature in meteorology.

   The upper-case letter Θ is used as a symbol for:
     * Dimensionless temperature in transport phenomena.
     * Big O notation. Denoting an asymptotically tight bound in analysis
       of algorithms.
     * Θ (set theory), a certain ordinal number.
     * Representing pentaquarks, exotic baryons in particle physics.
     * Earth Day.
     * Brainwave Frequency (Beta, Alpha, Theta, Delta) ranging from 4-8 Hz

Use in Options Investing

     * Theta is known as an option greek measuring the rate of time decay
       on a daily basis. One can look as this as an ice cube melting in
       your hand. A Theta of -.05 means that the option is losing a nickle
       of time value each day. Other option greeks include Delta, Vega,
       Rho and Gamma.

Uses as names

     * Theta Sigma is the nickname of the Doctor of the television series
       Doctor Who

   Retrieved from " http://en.wikipedia.org/wiki/Theta"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
