Erdélyi is a word of Hungarian origin, meaning “related to Transylvania”.
Arthur Erdélyi (1908–1977) — Hungarian-born British mathematician
János Erdélyi (1814–1868) — Hungarian poet, critic, author, philosopher and ethnographist
Stefan Erdélyi (1905–1968) — Hungarian-Romanian chess master
Tamás Erdélyi — professor of mathematics at Texas A&M University
Vasile Erdelyi (1794–1862) - Romanian Greek Catholic bishop of Oradea Mare
Tommy Ramone aka. Thomas Erdelyi, born Erdélyi Tamás (b. 1952) — Hungarian American record producer and musician