Out to the ocean or to the sea. Hawaiian word created from the words ma, meaning to go to or to move towards, and Kai meaning ocean or sea.

Noun: a friend who is usually only called upon by a friend when a more primary/prominent friend is unavailable.

Taken from the term “second string” in an athletic competition situation. In football, if the star quarterback gets injured during a play, the second string is called off the bench to replace him/her. A “Second String Friend” is essentially benched until needed, if ever.

Synonyms: Plan B, Second Choice, Secondary Friend, Benched Until Needed

Means ocean or beachside in HAWAIIAN- Most commonly used in giving directions.

He is so handsome, polite , and one of the most polite people you will ever meet.

One of the "realms" or "worlds" discussed and dealt with in anime such as Yu Yu Hakusho, specifically. In this anime, there are three: Makai-demon world; Reikai-spirit world; and Ningenkai-human/mortal world.
It is from this place that all demons originated, infiltrating human world through portals.
The control of these portals becomes a major issue in the series.
Later on, introduced as being ruled by three strong demons, Yomi, Raizen, and Mukuro.