The term 'catholicon' is a Greek word meaning 'universal REMEDY'. It is used to refer to a substance or treatment that is believed to cure all diseases or ailments. The crossword solutions for the term 'catholicon' are PANACEA (7 letters), ELIXIR (6 letters), REMEDY (6 letters), and cureall (7 letters). All of these words refer to a substance or treatment that is believed to have healing properties. PANACEA and ELIXIR are often used to refer to a magical or mythical substance, while REMEDY and cureall are more general terms for any type of healing substance or treatment.