pneumenoultramicroscopicillivolcanoconiosis

ˌnju mə(ʊ)nəʊˌʌltrəˌmʌɪkrə(ʊ)ˈskɒpɪkˌsɪlɪkəʊvɒlˌkeɪnəʊˌkəʊnɪˈəʊsɪs

an invented long word said to mean a lung disease caused by inhaling very fine ash and sand dust.

Doctor: Sir, have you inhaled any ash or sand dust?

Patient:Yes.

Doctor:Well i'm afraid you might have pneumenoultramicroscopicillivolcanoconiosis.

Patient:what