先せん投とうMeanings1nounstarting pitcherBaseball term for the pitcher who starts the game. Often used in sports news and commentary.今日きょうの先せん投とうは山やま田だ投とう手しゅです。Today's starting pitcher is pitcher Yamada.先せん投とうが初しょ回かいから好こう投とうを見みせた。The starting pitcher pitched well from the first inning.