Sumas noun6 •Ellipsis of Sumas Mountain. •Ellipsis of Sumas Lake: a former lake in the Fraser Lowland region, shared between British Columbia, Canada and Whatcom County, Washington, United States, which was drained to create Sumas Prairie. •Ellipsis of American Sumas: a mountain in the Skagit Range, Whatcom County, Washington, United States. •Ellipsis of Canadian Sumas: a mountain in British Columbia, Canada. •Ellipsis of Sumas Peak: a peak on Canadian Sumas Mountain, British Columbia, Canada. •Ellipsis of District of Sumas: a former district of British Columbia, Canada in the Fraser Lowland, that was merged into Abbotsford; now called Sumas Prairie.