(1846-48) a war between the US and Mexico, which began when Texas, which had recently become independent from Mexico, became part of the US. Mexico and the US disagreed over the Texas-Mexico border. The US also wanted to buy California and New Mexico, but Mexico did not want to sell them. Led by Zachary Taylor, the US won the war, and bought a very large area of land, which included California, Nevada, Utah, and parts of several other states.
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.
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