The phrase "significant investment" refers to a large amount of money or resources that is put into something, typically with the expectation of generating returns or achieving a particular goal. This could mean spending a lot of time and effort in developing a project, purchasing expensive equipment or property, or making a substantial financial commitment towards an idea or venture. The term implies that the investment is noteworthy due to its size or importance, and it reflects a high level of commitment from whoever is making the investment.