sponsorn.[L., from spondere, sponsum, to engage one's self. See Spouse.]1. One who binds himself to answer for another, and is responsible for his default; a surety.()2. One who at the baptism of an infant professes the Christian faith in its name, and guarantees its religious education; a godfather or godmother.()3. A person who vouches for another as fit for some post or task; as, one needs two sponsors to be considered for membership.()4. A person or group that assumes financial responsibility for some activity, and may or may not participate in its organization and execution.()5. A person or organization, usually a commercial organization, which pays the cost of an activity, such as a radio or television broadcast, and in return is given the right to advertise itself or its products as part of the activity; as, now a word from our sponsor.()