catechesis

[kat-i-kee-sis]
noun, plural cat·e·che·ses [kat-i-kee-seez] /ˌkæt ɪˈki siz/.
  1. oral religious instruction, formerly especially before baptism or confirmation.

Origin of catechesis

1745–55; < Late Latin < Greek katḗchēsis oral teaching, equivalent to katēchē- (variant stem of katēcheîn to teach by word of mouth; see catechist) + -sis -sis
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for catechesis
n.

from Greek katekhesis "instruction by word of mouth," from katekhein "to instruct orally," originally "to resound" (with sense evolution via "to sound (something) in someone's ear; to teach by word of mouth." From kata- "down" (in this case, "thoroughly") + ekhein "to sound, ring," from ekhe "sound," from PIE *(s)wagh- "to resound" (see echo (n.)). Related: Catachectic; catachectical.

Online Etymology Dictionary, © 2010 Douglas Harper