al-Qae·da or al-Qai·da (?l-k??d?, -k??d?)n. An international organization of loosely affiliated cells that carry out attacks and bombings in the attempt to disrupt the economies and influence of Western nations and advance Islamic fundamentalism.[Arabic al-q?’ida, the base : al-, the + q?’ida, base, feminine active participle of qa’ada, to sit; see q?d in Semitic roots.]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.