To reduce in number, especially personnel: “The company decided to downsize half the workers in the aircraft division.” It can also be used in reference to objects: “I decided to downsize my wardrobe and threw out all my old T-shirts.”
Note: Downsize is a recent euphemism for “fire, lay off.” Company managers often use this term in an attempt to soften the blow of wide-scale layoffs.
To reduce the size of a company by eliminating employees, in order to increase profits (1980s+)