Learned borrowing from Latin Quīntīlis (“Fifth Month”).
Quintilis
From quīntus (“fifth”) + -īlis, due to its position in the Roman calendar prior to the establishment of Iānuārius (“January”) as the first month. As a noun, ellipsis of Quīntīlis mēnsis m (“fifth month”).
Quīntīlis (neuter Quīntīle); third-declension two-termination adjective
In Classical Latin, month names were regularly used as adjectives, generally modifying a case-form of mēnsis m sg (“month”) or of one of the nouns used in the Roman calendar to refer to specific days of the month from which other days were counted: Calendae f pl (“calends”), Nōnae f pl (“nones”), Īdūs f pl (“ides”). However, the masculine noun mēnsis could be omitted by ellipsis, so the masculine singular forms of month names eventually came to be used as proper nouns.[1]
The accusative plural adjective forms Aprīlīs, Septembrīs, Octōbrīs, Novembrīs, Decembrīs[2] are ambiguous in writing, being spelled identically to the genitive singular forms of the nouns; nevertheless, the use of ablative singular forms in -ī and comparison with the usage of other month names as adjectives supports the interpretation of -is as an accusative plural adjective ending in Classical Latin phrases such as "kalendas Septembris".[3]
Third-declension two-termination adjective.
singular | plural | ||||
---|---|---|---|---|---|
masc./fem. | neuter | masc./fem. | neuter | ||
nominative | Quīntīlis | Quīntīle | Quīntīlēs | Quīntīlia | |
genitive | Quīntīlis | Quīntīlium | |||
dative | Quīntīlī | Quīntīlibus | |||
accusative | Quīntīlem | Quīntīle | Quīntīlēs Quīntīlīs |
Quīntīlia | |
ablative | Quīntīlī | Quīntīlibus | |||
vocative | Quīntīlis | Quīntīle | Quīntīlēs | Quīntīlia |
Quīntīlis m sg (genitive Quīntīlis); third declension
Third-declension noun (i-stem, ablative singular in -ī).
singular | plural | |
---|---|---|
nominative | Quīntīlis | Quīntīlēs |
genitive | Quīntīlis | Quīntīlium |
dative | Quīntīlī | Quīntīlibus |
accusative | Quīntīlem | Quīntīlēs Quīntīlīs |
ablative | Quīntīlī | Quīntīlibus |
vocative | Quīntīlis | Quīntīlēs |