pickfirst base . first base {n. phr.} 1. The base that must be touched first by a baseball player after batting. He got to first base on four balls. 2. See: GET TO FIRST BASE. Categories: add yours noun Source: A Dictionary of American Idioms 'first base' on video MLB | Rare and strange Plays on first base MLB Amazing First Base Scoops How To Play First Base - 8 Simple Tips For First Base SF@WSH: Harper injures knee slipping on first base sort: relevance, mode: exact match, q: "first base", maxResults: 4, videoEmbeddable: true, videoSyndicated: true, safeSearch: strict, type: video Subscribe to: American IdiomsEnglish Slang Discuss