2-hydroxyethyl
2-methyl-1-butanol
2-methyl-1-pentene
2-n-hexyl-2-cyclopentene-1-one
2-nitropropane
2-propylene
2T
2-trichloro-1
2'-trifluoroethane
360-degree
  3-axis
3-butylene
3-D
3D
3-dimension
3H
3-methyl-1-pentyn-3-ol
3-methyl-2-butene
3-pole
3-position
4-acetyl-6-tert-butyl-1