That depends entirely on what characters are used to write it. For example, written 春姫 (as in Kamisaka Haruhi from the game and anime Happiness!) it means 'spring' and 'princess', but written 晴日 (as in singer Aiso Haruhi) it means 'clear weather' and 'day' or 'sun'. It's also commonly written in hiragana (as はるひ) or katakana (as ハルヒ), which is phonetic spelling; the characters have no meaning.
Since I suspect it might be why you're asking, both Suzumiya Haruhi's and Fujioka Haruhi's (Ouran High School Host Club) given names are written in katakana.
"Hikari" means light. "Hikaru" however, means shining.
The name Hikaru means light in japanese.
The name Hikaru is of Japanese origin and means "shining" or "radiant." It is a unisex name often given to both boys and girls.
Spring
It means light in japanese.
Hikaru Kurosaki's birth name is Seiki Kurosaki.
Hikaru Kawamura's birth name is Shinozaki Yukie.
Hikaru Yamauchi's birth name is Sz Okada.
Hikaru Nanase's birth name is Masumi Niita.
Yes it can, and it is.
Hikaru Sulu
Hikaru and Kaoru Hitachiin are awesome because they are Hikaru and Kaoru Hitachiin. I mean, come on, there probably isn't one person on Earth who doesn't want to be them (or at least one of them).
I believe you mean Lt. Hikaru Zulu who was portrayed by George Takei
Yes his name is Yaotome Hikaru
Yes. His twin's name is Kaoru.
NO!!!!!!!! Keiko Fuji, whose real name is Junko Utada the mother of Utada Hikaru killed herself she was 62