An industrial unit of production equal to the work one person can produce in a day.(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.
Use "man-day" in a sentence
"The surplus of mechanical energy gained would thus be 26 horsepower-hours, or the equivalent of 26 man-days per man-day."
"At 2 percent the surplus would be increased to 53 man-days per man-day."
"From the point of view of the total energy generated, if not of the surplus per man-day, the clipper ships were paramount."