Hagiography - hagiolatry - hagiology
All these words are pronounced with the stress on the third syllable (i.e., the 'o') and with the first 'g' hard, as in 'get', not soft as in 'range'. (Think of the prejudicial word for an unattractive old woman 'hag'.) The final 'g' in hagiology, however, is soft (see -ogic, -ogue, -ogy). Thus the three words are pronounced, respectively, IPA: /,hæ gɪ 'ɒ grə fɪ/, /,hæ gɪ 'ɒ lə trɪ/, and /,hæ gɪ 'ɒ lə dʒɪ/.
All these words come from Greek, where hagios (ἅγιος) means 'saint'. Hagiography means '[writing] the life of a saint'; hagiolatry is 'worship of a saint'; and hagiology is 'study of the saints'.