Possible Clues:

• Feature of a two-ltr. monogram
• Abbr. for people with only two names
• Application form abbr.
• Abbr. for those with only one given name
• Abbr. for someone with only one given name
• Application letters
• Abbr. for people lacking parts of names
• Document placeholder
• Abbr. between a first and last name, maybe
• Abbr. for two-name people