There is this Urdu word Sajda / Sajdah that keeps on appearing in Hindi songs forever. Sajda is an Arabic word meaning prostration to God in the direction of the Kaaba at Mecca which is usually done during the daily prayers.
In simpler terms, Sajda is a posture in prayer where one bends one's head in submission to God. The word Sajda is used by the poets/lyricists because a Sajda is considered the utmost stage of submission. And hence when someone says s/he performed a sajda, it means s/he devoted himself / herself completely to someone else.