NCIt definition : Liquid preparation consisting of a liquid active substance per se, such as an essential
oil or a volatile anesthetic, intended for generation of vapor to be inhaled. The
vapor may be generated by adding the liquid to hot water or by the use of a vaporizing
device.;
Alternative definition : EDQM-HC: Liquid preparation consisting of a liquid active substance per se, such as
an essential oil or a volatile anaesthetic, intended for generation of vapour to be
inhaled. The vapour may be generated by adding the liquid to hot water or by the use
of a vaporising device.;