radial engine

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An internal-combustion engine, formerly used in propeller-driven aircraft, with cylinders arranged radially around the crankshaft.

from the GNU version of the Collaborative International Dictionary of English.

• (Mach.) An engine, usually an internal-combustion engine of a certain type (the radial type) having several cylinders arranged radially like the spokes of a complete wheel. The semiradial engine has radiating cylinders on only one side of the crank shaft.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Any of several internal combustion engines that have the cylinders arranged radially around a central crankshaft

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an internal-combustion engine having cylinders arranged radially around a central crankcase