On Educative: Interactive Courses for Software Developers you say:
A seeder is a node that hosts the data on its system and provides bandwidth to upload the data to the network, and a leecher is a node that downloads the data from the network.
In GENERAL peer-to-peer discussion, a leecher is a node that consumes from the network without contributing back. A regular participating node both offering and consuming services and resources would not be considered a leech. The exception to this would be Bittorrent, where any consuming node is called a leech, even if it is also providing seeds and uploading data.