You searched for: “chronograms
chronogram (s) (noun), chronograms (pl)
1. An inscription, sentence, or phrase in which certain numeral letters, usually made especially conspicuous to express a particular date or epoch on being added together; as in: Man of sCience and huManity, Bertrand RusselL’s eXample gIves life eXtra meaning = MCMLXIX or 1969, the year of Bertrand Russell’s death.
2. In horology, the record produced by an instrument that records time intervals; A chronogram is the document showing the duration of an event.