This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
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n. The principal landmass of a continent.

n. The main landmass of a country or continent

n. The continent; the principal land; -- opposed to island, or peninsula.

n. The continent; the principal land, as distinguished from islands.

n. The principal island of a group: as, the mainland of Orkney.

n. the main land mass of a country or continent; as distinguished from an island or peninsula

"You may have not realised when I was using the term mainland Europe, I was excluding the British Isles."

island    peninsula   

dry land    ground    land    terra firma    earth    solid ground   

continent   

land    main    continent   

peninsula    coast    continent    archipelago    frontier    coastline    Highlands    seaport    seaboard    promontory