1. United States astronomer who discovered the planet Pluto (1906-1997)
   - Clyde Tombaugh, Clyde William Tombaugh

Type of: astronomer, stargazer, uranologist

• second sight
• second stomach
• second string
• second thought
• second to none
• second trimester
• Second Vatican Council
• second wind
• Second World War
• second-degree burn
• second-guess
• second-hand speech
• second-hand store
• second-in-command
• second-place finish
• second-rate
• second-rater
• second-sighted
• second-stringer
• second-year
• secondarily
• secondary
• secondary amenorrhea
• secondary cell
• secondary censorship