[dcewcrrec]

You have to have the trademark approved, and they don't really care how big your company is, they will not approve a trademark for the word silicon. See: clothing brand Supreme's attempt to trademark their Supreme logo on a red background.

If apple combines the word with a unique logo or combines it with some other word, they can get the trademark, but you can't get it for the word silicon by itself.

[jedberg]

Apple has a trademark on the word Apple in the computer space.

[CraftThatBlock]

Yes, but silicon is a common word in tech.

[JimDabell]

"Windows" was a common word in tech, but Microsoft managed to get a trademark on that.