Vocation comes from the Latin “vocare” (to call). I think of vocation as an affirmed call from God to live out one’s Baptism in a specific state in life and role in The Church and this includes the secular laity: - married life, single celibate life ('single 'state).
Undoubtedly perhaps, pre V2, “vocation” in Catholic cultural terms was thought of as either religious life and/or the priesthood. The Sacrament of Marriage arrived a little later on the scene as a vocation per se. Nowadays, and especially since the various documents out of Rome on the laity, the lay celibate state is finding it’s feet as a vocation per se in Catholic cultural and theological thought. This is both that transitional lay celibate state where one is or is soon to discern their life vocation as well as those in the single celibate state as their actual life’s call and vocation and some of this latter group may be called to vow privately the evangelical counsels (not advisable without sound spiritual direction). This latter group (private vows to the egangelical counsels in the lay secular state) is mentioned in the document “Vita Consecrata” (The Consecrated Life) under the sub heading “Thanksgiving for the Consecrated Life”.
As St John Paul II said “Every life has a vocation” (see quotation box below).
**Catholic Culture **(sound Catholic resource site)
Excerpt only :
"In religious talk, the word vocation refers to three different things:
First is the common Christian vocation, which comes with baptism and is shared by all members of the Church. It consists in the commitment of faith and what follows from it: loving and serving God above all else, loving and serving neighbor as oneself, and collaborating in continuing the redemptive work of Christ, which is the mission of the Church.
The second meaning is state in life. A “state” puts some flesh on the bones of the common Christian vocation. It’s a broad, overarching commitment to a particular Christian lifestyle. As such, a state in life sets someone choosing it on a path that will shape his character through the countless choices and actions required to follow it to the end. **The clerical life, the consecrated life, the state of marriage, and the single lay state in the world are states in life. **
Third is personal vocation. It’s the unique combination of commitments, relationships, obligations, opportunities, strengths, and weaknesses — understood as representing God’s will — in and through which the common Christian vocation and a state in life are expressed by someone (priest, religious, layperson) trying to know and live the life God has in mind for him. It is the singular, unrepeatable role in his redemptive plan that God intends for each of us.
“Every life is a vocation,” Pope John Paul II says. And so it is — a unique, personal vocation."