Occurring as or resulting from coincidence.(adjective)
Happening or existing at the same time.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "coincidental" in a sentence
"How coincidental is it that it falls on the eve of the inauguration of our first black president?"
"While it seems to be coincidental, the German word for 'Song' would be 'Lied', which actually is neuter."
"And how coincidental is it that he just happens to be working with Angus Scrimm, star of my all time favorite horror film ‘Phantasm.’"