A name made for a subdivision
Lanikai is not a traditional place name. It was coined in the 1920s by the developer Charles Frazier, who with Richard Trent was subdividing the beachfront and wanted something that would appeal to buyers. They combined lani (heaven) and kai (sea) and read it as 'heavenly sea'.
The grammar does not cooperate. Hawaiian puts the qualifier after the noun, so lani-kai reads closer to 'sea heaven'. 'Heavenly sea' in correct Hawaiian would be Kailani.
Kaʻōhao
The land already had a name: Kaʻōhao, which describes a tying together — the way the two ends of a lei or a rope are bound. The name refers to the area and its ahupuaʻa, and it has been returning to use. The neighbourhood's elementary school changed its name back to Kaʻōhao in 2018.
Using the older name is increasingly common among residents and is not a correction anyone will object to.
The beach
The shore looks out at the Mokulua islands, two seabird sanctuaries about a mile offshore. Landing on the smaller one is prohibited. The beach itself has narrowed substantially over recent decades as seawalls in front of private houses have interrupted the natural movement of sand.