What is the X in X-mas?
1825 (adj.), c.1830 (n.)., from Latin inhalantem, present participle of inhalare (see inhale).
inhalant in·ha·lant (ĭn-hā'lənt)adj. Used in or for inhaling. n. Something that is inhaled, especially a drug that is delivered to the respiratory passages by a nebulizer or an aerosol container.