The reproductive gland in a male vertebrate, the source of spermatozoa and the androgens, normally occurring paired in an external scrotum in humans and certain other mammals.
An analogous gland in an invertebrate animal, such as a hydra or a mollusk.
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.