
1) Epic
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https://www.crosswordclues.com/clue/tetralogy

1) Serial 2) Series
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https://www.crosswordclues.com/clue/tetralogy

A tetralogy (from Greek τετρα- tetra-, `four` and -λογία -logia, `discourse`) is a compound work that is made up of four distinct works. The name comes from the Attic theater, in which a tetralogy was a group of three tragedies followed by a satyr play, all by one author, to be played in one sitting at the Dionysia as part of a compe...
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http://en.wikipedia.org/wiki/Tetralogy

• (n.) A group or series of four dramatic pieces, three tragedies and one satyric, or comic, piece (or sometimes four tragedies), represented consequently on the Attic stage at the Dionysiac festival.
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http://thinkexist.com/dictionary/meaning/tetralogy/

Synonym: tetrad. ... Origin: G. Tetralogia ... (05 Mar 2000) ...
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http://www.encyclo.co.uk/local/20973

(tĕ-tral´ә-je) a group or series of four. tetralogy of Fallot a congenital heart defect consisting of four structural anomalies: obstruction to pulmonary flow; ventricular septal defect (abnormal opening between the right and left ventricles); dextroposition of the aorta (aorti...
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http://www.encyclo.co.uk/local/21001

(1) In a general sense, a collection of four narratives that are contiguous and continuous in chrono
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http://www.encyclo.co.uk/local/22385
Te·tral'o·gy noun [ Greek ...;
te`tra- (see
Tetra- ) + ... a speech, discourse: confer French
tétralogie .]
(Gr. Drama) A group or series of four dramatic pieces, three tragedies and one satyric, or comic, piece (or sometimes four tragedies), represented consequently ...
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http://www.encyclo.co.uk/webster/T/34

Type: Term Pronunciation: te-tral′ŏ-jē Synonyms: tetrad1
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http://www.medilexicon.com/medicaldictionary.php?t=91048

[
n] - a series of four related works (plays or operas or novels)
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http://www.webdictionary.co.uk/definition.php?query=tetralogy
noun a series of four related works (plays or operas or novels)
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https://www.encyclo.co.uk/local/20974

Greek tetra = four, and logos = discourse, hence a combination of four elements e.g., symptoms or defects.
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https://www.encyclo.co.uk/local/21450
No exact match found.