Wiktionary
prerhotic
a. (label en linguistics rare) Occurring before the letter ⟨r⟩ or before any one of the sounds that letter tends to represent (''e.g.'', (IPAchar: [r]), (IPAchar: [ɽ]), (IPAchar: [ɹ]), (IPAchar: [ɻ]), (IPAchar: [ʀ]), (IPAchar: [ʁ]), etc.).