• Webster's Revised Unabridged Dictionary
    • a Epistolic Pertaining to letters or epistles; in the form or style of letters; epistolary.
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Century Dictionary and Cyclopedia
    • epistolic Pertaining to letters or epistles; epistolary.
    • ***
Chambers's Twentieth Century Dictionary
    • adjs Epistolic pertaining to or consisting of epistles or letters: suitable to an epistle: contained in letters
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Webster's Revised Unabridged Dictionary
L. epistolicus, Gr.
Chambers's Twentieth Century Dictionary
O. Fr.,—L. epistola—Gr. epistolēepi, stellein, to send.


In literature:

Gelasius Epistol ad Andronicum, apud Baron.
"The History of The Decline and Fall of the Roman Empire Volume 3" by Edward Gibbon
Epistolize therefore first; flatter and sooth her with tender Lines.
"The Lovers Assistant, or, New Art of Love" by Henry Fielding
Julian is even thought to have "written for publication," as Latin epistolers of distinction had undoubtedly done before him.
"A Letter Book" by George Saintsbury
But I cannot think that Tennemann rightly interprets the Epistol.
"Plato and the Other Companions of Sokrates, 3rd ed. Volume I (of 4)" by George Grote