Bibliometrics:  According to the Oxford English Dictionary, bibliometrics deals "with the application of mathematical and statistical analysis to bibliography; the statistical analysis of books, articles, or other publications." 

Altmetrics (alternative metrics) are non-traditional metrics proposed as an alternative to the more traditional citation impact metrics, such as impact factor and h-index.

Impact factors can be applied to journals or to individual articles.  According to Journal Citation Reports, "The journal Impact Factor is the average number of times articles from the journal published in the past two years have been cited in the JCR year," although other time spans can be calculated.

Citation analysis examines the frequency, patterns, and graphs of citations in articles and books, using citations in scholarly works to establish links to other works or other researchers.  Identifying the number of times an article is cited by others is considered the "impact factor" for that article.