batubalanì
(n.) magnet
lit. bato (stone) + balanì (attraction, gravity, magnet)
Interestingly, KWF Diksiyonaryo does not provide a definition for "balanì", only a redirection to the definition for "gravity"
Related to this, the KWF Diksiyonaryo also offers the term "balaning-dagitab" as a translation of the term "electromagnet"
From "balani" (magnet) + "dagitab" (electricity, flash of light).
I tried doing a quick search on the origins of the word "dagitab"; I was under the impression that this is a newly coined term in Filipino. However, I couldn't find a source on that, and the more common "koryente" came from the Spanish "corriente". With this, I guess "dagitab" is the native Tagalog term. (I mean "native" as opposed to "borrowed" or "coined/neologism").
I think it was coined in “Maugnaying Talasalitaan”. Most of the terms coined there never caught on.