maiden name 
noun
The original surname of a married woman who uses her husband’s surname name after marriage: many women choose to work under their maiden names...
- In the last year of college, when everyone was trying to find a catchy ‘stage name’ I made lists and lists, researching old family names, maiden names, names that just sounded good.
- I kept my maiden name as a second middle name, but I'd not want to saddle any of my kids with it.
- Naomi would like to change her daughters' surname to her own maiden name.