stay gold means to remain young, true, true and complete, just like gold.
stay [ste? ]：n. ? Stay, stay; Stop; Stop; Delay, delay # pillar; v. ? Stay; Temporary residence; Stay; Continue, keep; Stop; Calm down, temporarily lift; Inhibition; Delay, delay; Rely on.
gold [g? ld]：n. ? Gold, gold, money; adj. ? Golden; Gold
for example:
stay gold. Stay true to yourself, to your friends and never let it go.
Never give up and insist on sincerity. To yourself or your friends.
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Lyrics in Rome:
Daisuki Dakara Zutto
Nannimo Shinpai Iranawa
My Darling, Stay Gold
Mujakini waratte kudasaina
Itsumademo…
Anata no hitomi no oku ni hisomu shounenn
Watashi no honnou kusugutte yamanai
Aah douka sono mama
Good Luck
Kanashii koto ha kitto
Konosakinimo ippai aruwa
My Darling, Stay Gold
Kizutsuku koto mo daijidakara
Daisuki dakara zutto
Nannimo shinpai iranaiwa
My Darling, Stay Gold
Mujakini waratte kudasaina
Itsumademo…
Shuushoku mo kimatte
Asondebakari irarenaine
Otona no joushiki ya chie mi ni tsukeru no mo i i
Aah Kyou ha konomama
Good Night
Kawariyuku no ga
Hito no kokoro no tsune dato iimasuga
Ne daarin Your Soul
Yasashiku kagayaki tsuzukeruwa
Daisuki dakara zutto
Nannimo shinpai iranaiwa
My Darling, Stay Gold
Mujakini waratte kudasaina
Itsumademo…
Daisuki dakara zutto
Nannimo shinpai iranaiwa
My Darling, Stay Gold
Mujakini waratte iraretara
Itsunohimo…