About 100 Italian American yesterday braved what one organizer called "this frigid fall day" to commemorate explorer Christopher Columbus and his discovery of America 486 years ago.

Gathering at Columbus Plaza in front of the National Visitor Center at Union Station, the Columbus Day celebrants watched U.S. Deputy Attorney General Benjamin R. Civiletti, representing President Carter, lay a wreath at the statue of Columbus there and heard a medley of marching music played by the U.S. Naval Academy Band and composed in honor of famous Americans.

"The idea (of sailing around the world) was not an original one," said Dr. Edmund D. Pellegrino, president of Catholic University, who called Columbus "a dreamer of dreams . . . who did not rest on his dreams."

Pellegrino praised what he identified as three ideals of Italian heritage - commitment to a democratic republic, the creative life of intellect and art, and Christian humanism - and said the voyage of Columbus "was a symbol of what man can do . . ."

But Lisa Sergio, a Florence-born specialist in international affairs, reminded the audience that had not Queen Isabella of Spain "pawned her jewels" to pay for the Columbus expedition, "we would not be here."

Prior to the Columbus Plaza gatherings, Columbus Day observers filled the National Shrine of Immaculate Conception for a special mass. Immediately following the wreath-laying at the Columbus statue yesterday, a cultural festival featuring Italian folklore was held in the plaza.

Sponsors of the event said it was the third year that organizers have attempted a national rather than a local focus on the annual celebration.