A.C. means: A.C. is a multi-use medical and physiological abbreviation. In clinical and anatomical contexts it stands for atriocarotid , axiocervical (relating to the axis vertebra and cervical region), or. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. As a place or proper-name reference it is purely descriptive. It is sporting vocabulary and harmless in itself.