(informal) succeed in the initial phase of a plan or
undertaking. The
phrase comes from the sport of
baseball, where a
base is one of four
stations, laid out in the
form of a diamond, which must be touched by a player after hitting the
ball. First
base is the first of these
stations the player must
reach.
—SHSBC Binder 29 Approved Glossary, —SHSBC Binder 31 Approved Glossary, —Class VIII №14, Approved November 1990, —PDC Volume 1 Approved Glossary, —Academy Level I Glossary - Approved November 1990