From Wiktionary, the free dictionary
Blend of jasy (“moon”) + peteĩ (“one”).
jasyteĩ
- January
- (Gregorian calendar months) Gyregório arapapaha jasy; jasyteĩ, jasykõi, jasyapy, jasyrundy, jasypo, jasypoteĩ, jasypokõi, jasypoapy, jasyporundy, jasypa, jasypateĩ, jasypakõi (Category: gn:Months)