Lunar month with the Sun one or two days before that evening ("e.g.", in the Islamic calendar). In ancient Egypt the lunar month began on the day when the waning moon could no longer be seen just before sunrise. Others use calculation, of varying degrees of sophistication, "e.g.", the Hebrew calendar or the ecclesiastical lunar calendar. Yet others run from full moon to full moon. Calendars count integer days, so months may be 29 or 30 days in length, in some regular or irregular sequence. In India the month from conjunction to conjunction is divided into thirty parts known as "tithis". The
Military designation of days and hours Military designation of days and hours The military designation of days and hours within the North Atlantic Treaty Organisation (NATO), is specified in AAP-6 (STANAG 3680), "NATO Glossary of Terms and Definitions", and marked "(NATO)" in what follows. Those entries marked "(US)" are specific to the U.S., and defined only in Joint Publication JP 1-02, "Department of Defense Dictionary of Military and Associated Terms". References to days (or hours) preceding or following a designated day (or hour) use a plus or minus sign and an Arabic numeral following the letter. For example, "D−3" is 3 days prior to D-day, "C+7"