Trench diseases back, also known as trench mouth, is a bacterial infection that causes painful, swollen gums, and ulceration. The spelling of the word trench (trɛnʧ) is pronounced with a "ch" sound, as in church, despite it being spelled with a "t" and an "r". The word diseases (dɪˈzizɪz) is spelled phonetically, with the emphasis on the first syllable. The word back (bæk) completes the phrase, with a simple phonetic spelling. Correct spelling and pronunciation of medical terms is important for clear communication and effective treatment.
Painful rigidity of the back affecting soldiers on trench duty, who are compelled to remain for long periods of time in a constrained position, at the same time exposed to wet and cold.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.