To put something somewhere and then forget its location; to mislay
"I can't find my keys because I must have misplaced them in the crowd yesterday."
In plain English: To misplace something means to lose it because you put it somewhere and then forgot where exactly that is.
"I cannot locate my keys because I misplaced them this morning."
Usage: Use misplace when you accidentally lose an item because it was set down in the wrong spot, distinguishing it from simply losing or forgetting where something is. This verb specifically implies that the object still exists but has been forgotten at a specific, albeit incorrect, location.
The word misplace is formed by combining the prefix mis- with place. It was first used to describe the act of putting something in an incorrect location.