from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A univalent radical, PH4, derived from phosphine.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the tetravalent positively-charged phosphorus cation R4P+
from the GNU version of the Collaborative International Dictionary of English
- n. The hypothetical radical PH4, analogous to ammonium, and regarded as the nucleus of certain derivatives of phosphine.
from The Century Dictionary and Cyclopedia
- n. A hypothetical compound, analogous to ammonium, formed by the union of four atoms of hydrogen and one of phosphorus (PH4).
phosph(o)- + (amm)onium.(American Heritage® Dictionary of the English Language, Fourth Edition)