sexual intercoursen.1. Sexual union between a male and a female involving insertion of the penis into the vagina.2. Sexual activity that includes insertion of the penis into the anus or mouth. 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.sexual intercourse n (Zoology) the act carried out for procreation or for pleasure in which, typically, the insertion of the male’s erect penis into the female’s vagina is followed by rhythmic thrusting usually culminating in orgasm; copulation; coitus. Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014sex?ual in?tercourse n. genital contact or coupling between individuals, esp. one involving penetration of the penis into the vagina. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.sex·u·al intercourse (s?k?sho?o-?l) The process by which sperm from the male is deposited in the female during sexual reproduction.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.