Definition of "secretion" [se•cre•tion]

• The process of secreting a substance, especially one that is not a waste, from the blood or cells: secretion of hormones; secretion of milk by the mammary glands. (noun)
• A substance, such as saliva, mucus, tears, bile, or a hormone, that is secreted. (noun)
• The act of concealing something in a hiding place. (noun)
• The act of stealing something secretly. (noun)

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.

• "In diabetes the insulin secretion is out of order."
• "This regulation of insulin secretion is maintained even when the pancreas is surgically reduced to one seventh of its normal mass, or when besides the intact pancreas in situ four others are grafted into the circulation."
• "The precise mechanism of melatonin secretion in the body is not well understood."