Hagane no kokoro?

I'm not sure but i'd say full metal heart if that's what Kokoro means...

I wouldnt rely and believe too much on google translator. It's good, but still, not perfect. Im goign them whit what Kokoro means: Fullmetal Heart.I hope I was of some help :)

For some reason, when subbers and such translate the names of Jappanese things into English they usually change it.
Like they translated the show: "Waganaria!!" to: "Working!!"
Now "Hataraite" means working but they didn't put it in the true translation.

I know this is an old question but "kokoro" in japanese doesn't meant the physical "heart" as in the organ, which is probably why google translate averts away from giving that answer to avoid confusion. "Kokoro" is more abstract, like "mind" or "soul" and yes, "spirit"--but not "spirit" as in "ghost".

It's one of those words where there's no LITERAL EXACT translation. It means "heart" in the same way as "That person there has HEART, you see how they persevered and didn't let the world drag them down?" Or it can mean spirit like in having team spirit or school spirit pride. It's all about the artistic license taken in the end by the translator with which English word to go with that best matches with the same intent in Japanese.

(I came here looking for the names of the seiyuu who sing this song, and other sites only kept giving Paku Romi but not the rest.... google results can be weird.)