critical mass (n) - the smallest amount of fissile material needed for a sustained nuclear chain reactionCritical Mass is a blog devoted to the liturgical catechesis of the faithful of the Catholic Church called for by Vatican Council II in its first document, the Constitution on the Sacred Liturgy, Sacrosanctum Concilium:
critical (adj) - characterized by careful, exact evaluation and judgment; indispensable, essential
Mass (n) - public celebration of the Eucharist in the Western Rites of the Catholic Church
With zeal and patience, pastors of souls must promote the liturgical instruction of the faithful, and also their active participation in the liturgy both internally and externally... [n. 19]