phyl·a·co·bi·o·sis \ˌfiləkōˌbīˈōsə̇s\noun (pluralphylacobioses) Etymology: New Latin, from phylaco- (from Greek phylak-, phylax guard) + -biosis : a mixobiosis in which ants of a particular species live in a termite nest and appear to replace functionally the nasute or soldier caste of the termite • phyl·a·co·bi·ot·ic\| ̷ ̷ ̷ ̷ ̷ ̷ˌbī|äd.ik -_bē|-\adjective