The phrase "endless supply" refers to an unlimited or inexhaustible amount of something. It suggests that there is more than enough of a particular resource, product or service available and it will continue to be so for an extended period of time. The term can be used in various contexts such as describing the abundance of natural resources like water or energy, the availability of products in a market, or the continuity of services provided by a company. In essence, "endless supply" implies that there is no shortage and that demand will always be met.