Part of the Bay of Bengal to the west of the Malay Peninsula WordNet 3.0 & Open English WordNet

The Andaman Sea is a marginal sea of the northeastern Indian Ocean bounded by the coastlines of Myanmar and Thailand along the Gulf of Martaban and west side of the Malay Peninsula, and separated from the Bay of Bengal to its west by the Andaman Islands and the Nicobar Islands. Wikipedia

Sea Wikidata

A body of water to the southeast of the Bay of Bengal, south of Myanmar, west of Thailand and east of the Andaman Islands; it is part of the Indian Ocean. OmegaWiki

Part of the Indian Ocean, to the southeast of the Bay of Bengal, south of Burma (Myanmar), west of Thailand, north-west of the Malay Peninsula, north of Sumatra, and east of the Andaman Islands. Wiktionary

Part of the Indian Sea west of the Andaman Islands and east of Thailand. Wiktionary (translation)