Mea culpa /ˌmeɪ.əˈkʊl.pə/ is a phrase originating from Latin that means my fault or my mistake and is an acknowledgment of having done wrong.[1] The expression is used also as an admission of having made a mistake that should have been avoided and, in a religious context, may be accompanied by symbolically beating the breast when uttering the words.
The phrase comes from a Western Christian prayer of confession of sinfulness, known as the Confiteor, used in the Roman Rite at the beginning of Mass or when receiving the sacrament of Penance. Grammatically, meā culpā is in the ablative case, with an instrumental meaning.