Names of the days of the week which is mainly based on a medieval version of Spanish, the five days of Monday–Friday closely follow the Spanish names. Sunday uses the Arabic name, which is based on numbering, because a Jewish language was not likely to adapt a name based on "Lord's Day" for Sunday. As in Spanish, the Ladino name for Saturday is based on "Sabbath". However, as a Jewish language—and with Saturday being the actual day of rest in the Jewish community—Ladino directly adapted the Hebrew name, "Shabbat". From Latin "Dominicus (Dominica)" or Greek Κυριακή (Christian Sabbath) After No Work. In Russian also "Day After Week(end)"
Determination of the day of the week that a year can start on, and leap years will alter the day of the week after February 29. This means that there are 14 configurations that a year can have. All the configurations can be referenced by a dominical letter, but as February 29 has no letter allocated to it a leap year has two dominical letters, one for January and February and the other (one step back in the alphabetical sequence) for March to December. For example, 2018 is a common year starting on Monday, meaning that 2018 corresponds to the 2007 calendar year and with the last