Half-island

Because of its half-island identity, the Korean peninsula has instilled among those who live along its coasts and on some of the over three thousand mostly small offshore islands, a long-term interest in fisheries.

Source: wiktionary

For some time, the Midianites controlled part of the AraBa territories of Negeb desert and the half Island of Sinai.

Source: wiktionary

Therefore, полуóстров is а half-island, or peninsula. Incidentally, the word peninsula is formed in the same way, from the Latin words раеnе (almost) and insula (island).

Source: wiktionary

Here the Chinese navy sees little but trouble and frustration in what Chinese strategists call the First Island Chain, which, going from north to south, comprises Japan and the Ryuku^([sic – meaning Ryukyu]) Islands, the “half-island” of the Korean Peninsula, Taiwan, [...]

Source: wiktionary