Sicily, Bali, Taiwan: Which Is an Island in an Archipelago?

All three are islands in archipelagos—but the question's framing suggests a single answer. Here's the precise geographic classification:

Sicily

• Island in: Mediterranean Sea
• Archipelago: None — it's the largest island in the Mediterranean, not part of an island chain. Nearby: Aeolian Islands (volcanic arc), Aegadian Islands, Pelagie Islands — separate groups.
• Political: Autonomous region of Italy

Bali

• Island in: Indonesian Archipelago (world's largest, 17,000+ islands)
• Sub-group: Lesser Sunda Islands (with Lombok, Sumbawa, Flores, Sumba, Timor)
• Political: Province of Indonesia

Taiwan

• Island in: Western Pacific
• Archipelago: Part of the Ryukyu-Taiwan-Philippines island arc system (geological). Politically disputed: claimed by PRC, governed by ROC.
• Nearby Groups: Penghu (Pescadores) — Taiwan's archipelago; Ryukyu (Japan); Batanes (Philippines)

Answer Depends on Definition

• "Archipelago" = volcanic island chain: Bali (Lesser Sundas)
• "Archipelago" = country of many islands: Bali (Indonesia)
• "Archipelago" = geological arc: Taiwan (Ryukyu arc)
• "Archipelago" = named group: None of the three is the namesake of its group (unlike Hawaii, Maldives, Philippines)

Most Accurate Single Answer

Bali — unambiguously part of the world's definitive archipelagic nation (Indonesia) and a named sub-archipelago (Lesser Sundas).

But geographically, all three are islands within larger island systems.