I should add that, although I've been writing today about truth in the ordinary sense of whether an idea corresponds to something that exists in reality, the Veritas with which the Dominican Order is primarily concerned is Jesus Christ.
Not facts about Jesus Christ. Not what the Church says about Jesus Christ. Not this or that Christology.
In practice, of course, Dominicans spend a lot of time talking about facts and what the Church says and this or that Christology. They also spend a lot of time talking about what's going on in the world and what should be done about it.
But before, behind, and beyond all that, the Truth a Dominican has to offer is the Person of Jesus Christ.
The post-conciliar period has been a time when the idea of apostolate has been stressed. Not just within the Dominican Family, but throughout the Church. Saying hello to people as they walk in a door is now a ministry. Googling "apostolate" returns more than 100,000 hits, "lay apostolate" more than 7,000. Religious sisters are out there (some are way out there) working in fields far beyond healthcare and education.
But before and behind and beyond all that must be Jesus Christ. Or else (as William Hinnebusch, OP, put it) you have people with active apostolates who have ceased to be apostles.