From Wiktionary, the free dictionary
Borrowed from Italian settembre, with the final -u being taken from Sicilian (see forms sittèmmiru, sittembru, sittèmmuru).
Settembru m
- September
- (Gregorian calendar months) xhur tas-sena fil-kalendarju Gregorjan; Jannar, Frar, Marzu, April, Mejju, Ġunju, Lulju, Awwissu, Settembru, Ottubru, Novembru, Diċembru (Category: mt:Months)