The word "mother mark" could be replaced by a range of synonymous words and phrases. For example, it could be substituted with "birthmark" or "beauty mark", which are both small marks on the skin that can be considered attractive features. Alternatively, "mole" or "blemish" could be used to describe a slightly larger and perhaps less desirable mark on the skin. In a different context, "maiden mark" could be used as a synonym, particularly in literature or poetry, to indicate a scar or mark that is symbolic of a character's life experiences or struggles. Ultimately, the choice of synonym would depend on the specific context of the sentence or piece of writing.