This is a direct reference to Sailor Uranus' affinity with the wind and sky and it's also a reference to the Japanese name for the planet Uranus: Ten'ousei.
While Tenoh is a correct romanization of Haruka's surname, it may also be correctly romanized as Tenou, Ten'ou, Ten'ō or Tenō. The ō is a marker for an elongated vowel. Takeuchi Naoko chose to use Tenoh when romanizing Haruka's name.
In the English Cloverway dub, Haruka's name is changed to Amara Tenoh. Coincidentally, Irwin toys released a Sailor Uranus doll well before Sailor Moon S was picked up in North America. The box for the doll cited her name as being Corrine.
Most dubs across the world chose to keep Haruka's original name, but there are some that chose to localize her name instead:
France: Frédérique
Hong Kong: Tin Wong Yiu
Hungary: Frédérique
Italy: Heles
Malaysia: Tin Wong Ying (Ah Ying for short)
North America: Amara Tenoh
South Korea: Teri (Anime), Rami (Manga)
Spain: Timmy Ten'ou
This translation alludes to Sailor Neptune's ability to control the seas. Michiru is a bit of a complicated name to translate, but it implies the rising of the seas. It's also a reference to the Japanese name for Neptune: Kaiousei.
Kaioh is the romanization that Takeuchi Naoko chose to use, but other correct spellings include Kaiou and Kaiō.
The Cloverway dub chose to change Michiru's name to Michelle Kaioh to make it more localized for an English speaking audience, akin to the other name changes throughout the series. Before this dub, Irwin toys listed her name as being Nerissa on their Sailor Neptune doll boxes.
Michiru's name is generally kept in most dubs across the world but there are some that decided to change it to something more localized:
France: Mylène
Hong Kong: Hoi Wong Mei Ji Lau
Hungary: Mylène
Italy: Milenia
Malaysia: Wong Michi lau
North America: Michelle Kaiou
Portugal: Mariana Kaioh
South Korea: Monika (Anime), Haeri (Manga)
Spain: Vicky Kaiou