The kanji 島島 primarily means "island" or "isle." It refers to a landmass that is completely surrounded by water.

・On-yomi (音読み): とう (tō) ・Kun-yomi (訓読み): しま (shima)

⚫︎ 島国 Translation: Island country ⚫︎ 島民 Translation: Islander; island residents ⚫︎ 沖縄の島 Translation: The islands of Okinawa

The kanji 島島 is a phono-semantic compound (形声文字, けいせいいもじ). ⚫︎ The left side is a radical (部首, ぶしゅ) meaning "mountain" or "hill" (山, やま). ⚫︎ The right side is a phonetic component, representing the sound of 島. The combination of the mountain radical and the sound component suggests a "mountain surrounded by water," hence the meaning "island."