366päevaseks

366päevaseks is an Estonian term that translates to "for 366 days" or "as 366 days old." This phrase is primarily used in the context of age, specifically when referring to a child who has completed one full year of life and is now in their second year, having lived for 366 days. This distinction is relevant due to the occurrence of leap years, which add an extra day (February 29th) every four years.

In a non-leap year, a child turns one year old after 365 days. However, in a leap year, a child born on or before February 29th would have lived 366 days by the time they reach their first birthday. Therefore, the term 366päevaseks accurately reflects this extended period for children born in a leap year. The concept is important for precise age tracking, especially in official records or when discussing developmental milestones in relation to a specific number of days. While standard age is usually counted in full years, 366päevaseks highlights the specific duration of life in instances influenced by the Gregorian calendar's leap year system.