Look up -graphy in Wiktionary, the free dictionary.
The English suffix -graphy denotes either a field of study or a manner of writing or representation. It derives from the French -graphie, which in turn comes from the Latin -graphia, itself a transliteration of the Greek -γραφία (-graphia).
Because -graphy begins with a consonant, it is usually joined to a combining form that provides the linking vowel -o- (e.g. photo- + -graphy). This follows the pattern of neo-classical word formation, in which new English words are built from Greek and Latin elements in imitation of Greek compound and derivative structures.