"Gypsy" is one of a large group of etymons, (such as "Gitan", "Gitano", "Kipti", "Yifti", "Kopte", "Magup" etc.) which ultimately derive from the spurious self-presentation by 8th century Byzantine fortune-tellers of themselves as the inheritors of ancient Egyptian wisdom. (Marsh 2008) The presentation included exotic dancing and music, and thus the essential elements of the "Gypsy" stereotype were in place more than 200 years before the Romani language was consolidated. Among those who took advantage of this ‘Egyptian’ identity were "Dom" who reached the east Mediterranean around the 9th century. When the first Romani speakers arrived in Anatolia in the 11th century, sounding and looking a bit like "Dom", we may speculate that Greeks and Turks alike saw them as a new set of 'Egyptians’: the Roma walked into a pre-existing stereotype.

This stereotype differs, however, from the other common European term for Roma, the 'tsigane/cigany’ etymon, which is thought to derive from a Byzantine Greek word for heretic, and was thus originally pejorative, and most often remains so, differing from the "Gypsy" etymon which originated in a prestigious identity. Marushiakova and Popov (2001) tell us that the two etymons were not used as synonyms before the 13th century, and they remain distinct today. In French, for example, "Gitans" and "Tsiganes" refer to quite different Romani ethnic groups. It is thus misleading, and often offensive, to translate the English word "Gypsy" by the pejorative term "Cigany". When Roma first reached England in the late 15th century, they told the English that they were "Egyptians". Some "Yifti" and "Magup" in the Balkans still insist that they are "Egyptians" not Roma.

English Romanichal and Irish Traveller activists and a German Sinte activist who attended the First World Romani Congress in 1971 all agreed that all Romani and Traveller groups should be covered by the ethnonym "Rom/Roma" even though the word had a different meaning in their dialects. But in Germany in the 1970s the condescension of immigrant Roma led to a backlash in which Sinte insisted on their own name being used. A similar reaction after the mass migration of East European Roma to the United Kingdom from the 1990s has led to English Romanichals in the UK insisting strongly on the legitimacy of the the English word "Gypsies" to describe themselves, although the same reaction has not occurred in North America, where Romanichal activists often support the Roma assertion that "Gypsy" is a demeaning exonym. But in England, former Gypsy Council chairman Joe G. Jones expressed majority sentiment when he said 'Our ancestors were killed because they called themselves Gypsies. Today we will not let anybody tell us we cannot call ourselves "Gypsies”!’ "Gypsies, Roma and Travellers" is now the English-English equivalent of German "Sinti und Roma" and Euro-English "Romas".

References:

Marsh, A.R.N. (2008) “No promised land”: history, historiography and the origins of the Gypsies. PhD thesis, University of Greenwich.
Marushiakova, E and Popov, V. Gypsies in the Ottoman Empire: A Contribution to the History of the Balkans, University of Hertfordshire Press, Hatfield Source: Thomas Acton