The name "Maslo" at first glance derives from the Slavic appellative "maslo," meaning "butter." However, it is also possible that it is a truncated variant of one of the ancient Slavic compound names, such as "Maslomet" or "Masloboh," as reproduced by Professor H. Buchko and Associate Professor H. Buchko based on ancient Ukrainian composite names. The earliest written mentions of the name "Maslo" in Ukrainian documents date back to the 16th-17th centuries. For example, in 1565, documents mention the names of the village heads of the Khmelnytskyi starostvo: Denis, Marko, Masło, Maxim, Steczko. In 1620, the individual Maslo Bondar from the town of Berezdiv is noted. Beginning in the 16th century, the anthroponym "Maslo" was also used in Ukraine and Belarus as an additional identifier of a person alongside their name. For instance, in 1552, the name Bohdan Maslo, a townsman from Mozyr, is recorded; in 1563 – Andrii Maslo, a peasant from Kremianets; in 1653 – Vasyl Maslo, a peasant from Kamianets. In 1552, the city of Mozyr also mentions the personal name "Masliuk" – Masliuk Kalynkovych. It is noteworthy to highlight the record of the name "Mazlan" from the Transcarpathian village of Chingava in 1574.