You searched for: “chronogram
1. A phrase, sentence, or inscription, in which certain letters (usually distinguished by size or otherwise from the rest) express by their numerical values a date or epoch.
2. 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.
3. In horology, the record produced by an instrument that records time intervals; such as, the duration of an event.