- polychlorinated dibenzo-pdioxins (PCDDs)
- poly(chlorinated halogenated olefin)
- polychloroether
- polychloroprene
- poly (chlorotrifluoroethylene)
- polychlorotrifluoroethylene
- poly (chlorotrifluoroethylene); polytrifluorochloroethylene (PCTFE)
- polychoric correlation
- polychoron
- polychroism
- polychroism, polychromatism
- polychromatic
- polychromatic fiber
- polychromatic group
- polychromatic light
- polychromatic percolation
- polychromatism
- polychromator
- Polychrome
- polychronism
- polycide
- polycircular region
- polycistron
- polycistronic mRNA
- polyclimax