The term 'Grow by Addition' can be summarized as the process of increasing or expanding something by adding to it. This is often done in business, where a company may add new products or services to its existing offerings in order to increase its revenue. The crossword solution for this term is 'ACCRUE, ' which means to accumulate over time. This could refer to the gradual increase in a company's profits or assets as a result of adding new products or services.