Numerals of uniform height matching the capitals, designed for use in titles, headings, and tabular settings. Also called lining figures.
Definition
Titling figures (also called lining figures or ranging figures) are numerals that share a uniform height, typically matching the capital letters, and sit on the baseline without descenders. They are the default numeral style in most modern typefaces and are well suited for headings, titles, all-caps settings, and tabular data where vertical alignment is important. In running prose, however, their uniform height can appear obtrusive compared to the more discreet text figures. Many well-equipped typefaces offer both titling and text figures, allowing the typographer to choose according to context.
Source
No access — Robert Bringhurst — p. 346:
Figures designed to match the uppercase letters. They are the same height as the caps and sit on the baseline.