Definition :
A pnictogen oxoacid which contains phosphorus and oxygen, at least one hydrogen atom bound to oxygen, and forms an ion by the loss of one or more protons.
Definition :
A compound which contains oxygen, at least one other element, and at least one hydrogen bound to oxygen, and which produces a conjugate base by loss of positive hydrogen ion(s) (hydrons).
Definition :
Any organophosphate oxoanion that is a negatively charged phospholipid, e.g. phosphatidylserine(1), phosphatidate(2), phosphatidylglycerol(1).