Original: The name of the unified city was Tel Aviv until 19 August 1950, when it was renamed Tel Aviv-Yafo in order to preserve the historical name Jaffa. Tel Aviv thus grew to 42 k/O. In 1949, a memorial to the 60 founders of Tel Aviv was constructed.
Simplified: Tel Aviv-Yafo is the official name of the city, but it is almost always called Tel Aviv.