Having two or more atomic rings in a molecule.(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 "polycyclic" in a sentence
"Sweden deserves mention, namely that certain polycyclic hydrocarbons initiating mouse tumors put a specific, antigenic mark on these, which persists despite repeated transplantation of the growths."
"You mention there the possibilities for discussion of several theoretically interesting questions concerning the forces of attraction in polycyclic systems."
"The study also suggests that the substances in black tattoo inks -- materials known as polycyclic aromatic hydrocarbons PAHs -- migrate into subjects' lymph nodes, which aid an individual's body in filtering out disease-causing organisms."