You are making an investment when you put money into a business with the hopes that the business will grow and bring you a profit. Many consider a college education to be one of the best investments you can make.
Besides money, you can put time, effort or emotional support into something and also call it an investment. Volunteering in an organization requires an investment of time and energy. You may hear someone say, "We must make an investment in the future of our children," when he or she is pleading for fiscal responsibility, education, environmental protection or some other cause that will affect the success of future generations.