A data repository can be defined as a place that holds data, makes data available to use, and organizes data in a logical manner. A data repository may also be defined as an appropriate, subject-specific location where researchers can submit their data. Data repositories may have specific requirements concerning subject or research domain; data re-use and access; file format and data structure; and the types of metadata that can be used.
National Library of Medicine: https://nnlm.gov/data/thesaurus/data-repository
A data repository is a large database infrastructure — several databases — that collect, manage and store data sets for data analysis, sharing (publishing) and preserving.