Buick is a division of the American automobile manufacturer General Motors (GM). Named for automotive pioneer David Buick, it was among the first American marques of automobiles, and was the company that established General Motors in 1908. Buick was the first production automobile maker in the world to equip its cars with overhead valve engines, which it did in the year 1904. 

For much of its existence in the North American market, Buick has been marketed as a premium automobile brand, selling luxury vehicles positioned above GM's mainstream brands, while below the flagship luxury Cadillac division. 

An overhead valve (OHV) engine, sometimes called a pushrod engine, is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with earlier flathead engines, where the valves were located below the combustion chamber in the engine block.

The camshaft in an OHV engine is located in the engine block. The motion of the camshaft is transferred using pushrods and rocker arms to operate the valves at the top of the engine.

In addition to wealthier buyers, Buick has also had a reputation of appealing to older buyers. In North America, Buick vehicles are almost always sold alongside GMC vehicles at joint dealerships, allowing the same dealer to market both upscale cars and trucks.

In 2017, Buick sold more than 1.4 million vehicles worldwide, a record for the brand. The main market is China, where 80% of Buick-branded automobiles are sold. Buicks are also sold in the United States, Canada, and Mexico.

According to en.wikipedia