Yo
- Yocto
- Prefix representing a multiplication of 10-24
- Yotta
- Prefix representing a multiplication of 1024
- Young, James
- Pioneered process of refining oil into Paraffin.
- Young Stellar Object
- The generic name for a star prior to its main sequence phase.
- Young′s Double-Slit Experiment
- A famous experiment which shows the wave nature of light.
- Young′s Modulus
- The modulus of elasticity is the slope of the stress-strain diagram in the linear region.