Question: What is the difference between catechists and deacons?
Answer: A catechist is simply one who teaches the Catholic Faith to students. He might be young or old, a man or a woman. The major requirement for being a catechist is a clear knowledge of the Faith and teaching skills adequate for imparting that knowledge to the students. Particularly in mission countries, the catechist program may be relatively well organized, with catechists maintaining mission chapels served by visiting priests.
A deacon is an ordained clergyman, ranking just below a priest. The diaconate is a Sacramental Order, received by all men who are to be promoted to the priesthood, and occasionally received by men who are not expected to proceed any farther. The deacon is allowed to preach, to witness marriages, and to distribute Holy Communion if no priest is available to do so. The deacon ministers directly to the priest at Mass, wearing the vestments proper to his rank: amice, alb, cincture, maniple, stole (over the left shoulder) and dalmatic. Apart from the Mass and solemn Offices, the liturgical garb of the deacon is the cassock and surplice together with a stole worn over the shoulder.
One who is ordained a deacon remains one for eternity, as the Sacrament of Orders imparts a permanent character. One who is married, and whose wife dies, is unable to marry again.