According to the ALA TechSource, bibliometrics is a quantitative field with connections to sociology of science, science policy, and research program evaluation. Bibliometrics measures research outputs, especially articles in peer-reviewed journals, often in terms of publication counts, citation counts, and measurements derived from these (such as publications per year or journal impact factors, which are roughly citations per article over a certain period of time).

ALA TechSource: https://journals.ala.org/index.php/ltr/article/view/7921/11023
Image Source: https://www.frontiersin.org/journals/research-metrics-and-analytics/articles/10.3389/frma.2021.742311/full