symptom
a sign that shows you have an illness /ˈsɪmptəm/
prescription
a written instruction from a doctor for medicine /prɪˈskrɪpʃən/
allergy
a bad reaction your body has to certain things /ˈælərdʒi/
surgery
a medical operation done by a doctor /ˈsɜːrdʒəri/
Examples
“The main symptom is a sore throat.”
“The doctor gave me a prescription.”
“I have an allergy to cats.”
“He needs surgery on his knee.”