From The Collaborative International Dictionary of English v.0.48 :
Quadragesima \Quad`ra*ges"i*ma\, n. [L., fr. quadragesimus the
fortieth, fr. quadraginta forty; akin to quattuor four. See
Four.] (Eccl.)
The forty days of fast preceding Easter; Lent.
[1913 Webster]
Quadragesima Sunday, the first Sunday in Lent, about forty
days before Easter.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
Quadragesima
n 1: the first Sunday in Lent [syn: Quadragesima,
Quadrigesima Sunday]