Causerie is a French word that came into English in the 19th century. In both languages, it means a social chat or discussion (particularly on a particular topic such as literature, but still in a relatively light way); or in writing, an informal essay or piece of criticism in a personal, conversational tone. This written sense derives from a series of weekly columns starting in 1849 in the French newspaper Le Constitutionnel, by the author Charles-Augustin Sainte-Beuve entitled "Causeries du lundi" (Monday Chats).
It comes from the French verb "causer" (to chat), and eventually from Latin "causari" (to plead, discuss), from "causa" (case, cause).
"Causerie" is also the title of a poem by Charles Baudelaire from his collection Les Fleurs du Mal, originally published 1857. Its title has been variously translated into English as "Conversation," "Episode," or "Talk."
Causerie
Vous êtes un beau ciel d'automne, clair et rose!
Mais la tristesse en moi monte comme la mer,
Et laisse, en refluant sur ma lèvre morose
Le souvenir cuisant de son limon amer.
-- Ta main se glisse en vain sur mon sein qui se pâme;
Ce qu'elle cherche, amie, est un lieu saccagé
Par la griffe et la dent féroce de la femme.
Ne cherchez plus mon coeur ; les bêtes l'ont mangé.
Mon coeur est un palais flétri par la cohue;
On s'y soûle, on s'y tue, on s'y prend aux cheveux!
-- Un parfum nage autour de votre gorge nue!...
Ô Beauté, dur fléau des âmes, tu le veux!
Avec tes yeux de feu, brillants comme des fêtes,
Calcine ces lambeaux qu'ont épargnés les bêtes!
Lousy translation by me and Babelfish (It's been 13 years since I last studied French):
You are a beautiful autumn sky, clear and pink!
But my sadness rises like the sea,
Leaving when it ebbs, on my morose lips,
The burning memory of its bitterness.
--In vain your hand slides on my swooning chest;
The place you seek, my dear, has been left pillaged
By the claws and the wild fangs of women.
Do not search for my heart any more; the animals devoured it.
My heart is a palace overrun by rioters;
They get drunk there and kill each other,
or just grab each other by the hair
-- A perfume swims around your naked throat!
Beauty, cruel plague of souls, you want it!
With your eyes of fire, brilliant as festival lights,
Burn through these scraps which the animals left behind!
Sources:
http://www.wordsmith.org/words/causerie.html
http://dictionary.reference.com/search?q=causerie
http://www.thefreedictionary.com/causerieM
http://www.hyperdictionary.com/dictionary/causerie
http://www.webster-dictionary.org/definition/causerie
http://www.tiscali.co.uk/reference/dictionaries/difficultwords/data/d0003171.html
http://www.bartleby.com/61/32/C0173200.html
http://encarta.msn.com/dictionary_1861595579/causerie.html
http://www.britannica.com/eb/article?eu=137479&tocid=0&query=causerie&ct=
http://www.britannica.com/eb/article?eu=66641&tocid=6378&query=causerie&ct=
http://www.newsandmedia.hik.se/paper_online/text/article_types.html
http://www.fleursdumal.org/poem/150
http://poesie.webnet.fr/poemes/France/baudelai/42.html
http://agora.qc.ca/reftext.nsf/Documents/Tristesse--Causerie_par_Charles-Pierre_Baudelaire
http://www.poetes.com/baud/bcauserie.htm | 
