Definition of in halves:
(v) :
(intransitive) To draw air into the lungs, through the nose or mouth by action of the diaphragm.
(v) :
(transitive) To draw air or any form of gas (either in a pure form, or mixed with small particles in the form of aerosols/smoke, sometimes stemming from a medicament) into the lungs, through the nose or mouth by action of the diaphragm.
(v) :
(transitive, figuratively) To eat very quickly.
(n) :
An inhalation.