mesiac

Mesiac is a Slovak word with two primary senses. In lowercase, it denotes a calendar month, a period of about 30 days used in the annual Gregorian calendar. In this sense it is a time unit and a unit of measurement in everyday and formal language, as in mentions of a specific month or monthly schedules. The concept of a month derives from historical ties to the Moon’s cycle, and cognate terms exist in other Slavic languages (for example Czech měsíc, Polish miesiąc, Russian mesyats). The length of months in the modern calendar varies between 28 and 31 days, and the term is not tied to a single lunar period.

When capitalized as Mesiac, the word refers to Earth’s Moon, the natural satellite that orbits our planet. The Moon is about 384,400 kilometers from Earth on average and is tidally locked, meaning the same hemisphere faces Earth most of the time. Its sidereal orbital period is about 27.3 days, while the synodic period—cycle of lunar phases from one new moon to the next—lasts about 29.53 days. The Moon’s surface features include maria, highlands, craters, and linear rays. It has been the subject of extensive scientific study and was the focus of crewed space missions in the 1960s and 1970s.

In summary, mesiac can refer to a month in the calendar or to the Moon, depending on capitalization and context, reflecting the historic link between timekeeping and the Moon’s cycle.