The seven names of Gondolin.

[piosenniel]

Then said Tuor: “What be those names?” And the chief of the Guard made answer: “ ‘Tis said and ‘tis sung: ‘Gondobar am I called and Gondothlimbar, City of Stone and City of the Dwellers in Stone; Gondolin the Stone of Song and Gwarestrin am I named, the Tower of the Guard, Gar Thurion or the Secret Place, for I am hidden from the eyes of Melko; but they who love me most greatly call me Loth, for like the flower am I, even Lothengriol the flower that blooms on the plain.’ Yet,” said he, “in our daily speech we speak and we name it mostly Gondolin.”

--- The Fall of Gondolin; The Book of Lost Tales: Part II

Ondolindë (The Rock of the Music of Water) was its original Quenyan name given to the city by Turgon.

Gondolin is how it was referred to in Sindarin.