also: かいしん · わたつみ · わだつみ
Refers to a deity of the sea in Japanese mythology, or by extension to classical Western sea gods like Poseidon or Neptune. The readings わたつみ and わだつみ are archaic/poetic and specifically denote the Japanese sea god.
海神ポセイドンはギリシャ神話の神だ。
The sea god Poseidon is a deity in Greek mythology.
古事記には海神わたつみが登場する。
The sea god Watatsumi appears in the Kojiki.
Only with reading わたつみ / わだつみ
Archaic/poetic use, restricted to the readings わたつみ and わだつみ. Not used in modern standard Japanese; the common word for sea/ocean is 海 (うみ).
わたつみの底には龍宮城があると信じられていた。
It was believed that the Dragon Palace lay at the bottom of the sea.
海神 (かいしん) is the more standard modern way to write 'sea god,' while 海人 (かいじん) is an archaic variant used for the same deity.
Standard kanji spelling; the reading かいしん is the most common modern reading.
Alternate reading for the same kanji form; less common than かいしん.
Kana spelling for the archaic reading わだつみ, a variant of わたつみ.
Archaic/poetic kanji spelling for the sea god, using ateji. Associated with the reading わたつみ.
Kana spelling for the archaic reading わたつみ, used in classical contexts.
海神 is composed of 海 (sea) and 神 (god). The reading わたつみ is of native Japanese origin, likely from 海 (わた) + つ (archaic possessive particle) + 神 (み, an old word for spirit/god). The kanji 綿津見 is ateji for わたつみ.