- secondary structure
- secondary syphilis
- secondary tissue
- secondary wall
- secondary wave
- second banana
- second base
- second baseman
- second best
- second blessing
- second childhood
- second class
- second-class
- second-class citizen
- Second Coming
- second cousin
- second-degree burn
- seconded
- Second Empire
- second fiddle
- second-generation
- second growth
- second-guess
- second-guess
- secondhand