Si·kor·sky (s?-kôr?sk?), Igor Ivan 1889-1972. Russian-born American aviation pioneer. He designed (1939) the first successful American helicopter.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.