The word "decumary" is spelled as /dɪˈkjuːməri/. It is derived from the Latin word "decumerus," which means taking a tenth part. The word is primarily used to refer to a system of taxation in which one-tenth of a person's income or property is taken as tax. The spelling of "decumary" can be explained using IPA phonetics as follows: the initial sound is pronounced as /dɪ/ followed by a long "oo" sound pronounced as /uː/. The next syllable is pronounced as /mər/ followed by an "i" sound at the end pronounced as /i/.