Literally meaning: “humour caused by heat”
Origin: Anc Greek
φλέγω/phlego(=burn, send out fire)
The term is associated with the theory of humurism credited to Hippocrates. This thery reffered to four humours (yellow bile, blood, phlegm and black bile) that must be in balance in a healthy human body. According to Hippocrates, sickness resulted when the bodily humors became unbalanced. Among the four humours, phlegm is thought to cause apathy and this old belief is preserved in the word “phlegmatic”.
Phlegm is the mucus secreted by the mucous membrane of the respiratory tract.