Many will be surprised to hear this Latin phrase is the basis of the idiomatic “my bad” currently popular in American vernacular.

mea culpa (me·a cul·pa): / MEE uh KUHL puh | MAY uh KUHL puh / (always italicized)
noun

(1) a formal acknowledgment of personal error, responsibility, guilt, or fault

interjection

(1) expressing an admission of personal guilt or fault

[From Latin mea culpa meaning “(through) my fault.”]

Usage: Their earnest mea culpa did little to soothe hurt feelings.