This first edition of Field Manual FM 1-02.1 Operational Terms November 2019 compiles definitions of all Army terms approved for use in Army doctrinal publications, including ADPs, FMs, and ATPs. It also includes joint terms defined in the glossaries of Army doctrinal publications. FM 1-02.1 also lists shortened forms (whether considered acronyms or abbreviations) approved for use in Army doctrinal publications. In addition, FM 1-02.1 incorporates North Atlantic Treaty Organization (NATO) terms appearing in the glossaries of Army doctrinal publications. When communicating instructions to subordinate units, commanders and staffs from company through corps echelons should use this publication as a dictionary of operational terms and military symbols. FM 1-02.1 is organized as follows: Chapter 1 presents terms. Chapter 2 presents acronyms, abbreviations, and country codes. The terminology entries in chapter 1 of this publication fall into three categories: Definitions applicable to the Army only. Joint (DOD) definitions commonly used in Army publications. North Atlantic Treaty Organization (NATO) definitions commonly used in Army publications. For each term and definition, a proponent publication is cited in parentheses after the definition. The acronym and abbreviation entries listed in section I of chapter 2 are Army and joint. Shortened forms applicable only to Army doctrine are shown in boldface, to distinguish Army from joint usage. Acronyms are added to FM 1-02.1 and the online “Army Dictionary” when a defined term has an associated acronym or if an acronym has doctrinal cross branch or functional usage. The cross branch usage criterion for considering an acronym for inclusion is that it must appear in two or more doctrinal publications that are not branch specific or related. FM 1-02.1 is now the proponent of terms for which ADP 1-02 had been the proponent.