het·er·o·at·om 
(hĕtə-rō-ăt′əm)
(hĕtə-rō-ăt′əm)n.
An atom other than carbon or hydrogen in the structure of an organic compound, especially in a heterocyclic compound.
- postponement
- postpose
- postposition
- postpositional
- postpositionally
- postpositive
- postpositively
- postprandial
- postprandially
- postproduction
- postscript
- PostScript
- postseason
- poststructuralism
- postsynaptic
- postsynaptically
- posttest
- post time
- posttranscriptional
- posttransfusion
- posttranslational
- posttraumatic
- posttraumatic stress disorder
- postulancy
- postulant