"Watermark" is a song by Enya, an Irish singer, and composer, released as the lead single from her second studio album, also titled "Watermark," in 1988. The song is written and performed in the key of F major. Enya co-wrote the song with Roma Ryan, who wrote the lyrics, while Enya arranged and produced the song. "Watermark" became a major success for Enya, reaching the top 10 in several countries and establishing her as a prominent new age artist. Interestingly, the song was used in the 1991 BBC documentary series "The Celts," for which Enya provided the soundtrack. With its ethereal and atmospheric sound, "Watermark" features Enya's signature layered vocals, haunting melodies, and a captivating blend of synth-pop and Celtic influences.