Well, I did search for Aida on the web - and found it.
How anyone who had no knowledge of needlework stuff would get it is a mystery - as recondite as any other clue I can remember or imagine ... Perhaps this is education?
You are over complicating things. The poster already had A?DA. The google thing makes it instantly obvious what the answer is. No knowledge is required. This sort of thing happens a lot in crosswords across a wide range of subjects. As you say we learn something new everyday.