Triduum Paschale

Literally, “[the] three days of Paschal”, or more loosely translated as “[the] three days of [Easter]”.

• (Classical Latin) IPA^(key): [ˈtriː.du.ũː ˈpas.kʰa.ɫɛ]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈt̪riː.d̪u.um ˈpas.ka.le]

Trīduum Paschāle n sg (genitive Trīduī Paschāle); second declension

1. (Roman Catholicism) Paschal Triduum (period of three days that begins with the liturgy on the evening of Maundy Thursday)

Second-declension noun (neuter) with an indeclinable portion, singular only.