Manpower (noun)

1. The number of people available or required for a particular purpose, especially for work in an organization or industry.
2. The physical or mental ability of people, especially men, to do work or engage in physical activity.

Origin:

1930s: from man (noun) + power (noun).

Examples:

1. The company is short of manpower at the moment.
2. The project requires a lot of manpower to complete.
3. The factory relies heavily on manpower for production.
4. The company is going to invest in training to improve their manpower.
5. Manpower is the key to success in this business.