Inconveniently long words used frequently in related contexts can be represented according to their letter count. For example, "i18n" abbreviates "internationalization", a computer-science term for adapting software for worldwide use. The "18" represents the 18 letters that come between the first and the last in "internationalization". "Localization" can be abbreviated "l10n", "multilingualization" "m17n", and "accessibility" "a11y". In addition to the use of a specific number replacing that many letters, the more general "x" can be used to replace an unspecified number of letters. Examples include "Crxn" for "crystallization" and the series familiar to physicians for history, diagnosis, and treatment ("hx", "dx", "tx").