An Etymological Treatment of the Word Compassion
How are sympathy, empathy, passion and compassion related? Language-wise that is!
Notice how these four words all share the same letters 'pa'?
Many Greek words that start with the etymological root 'PA', have to do with 'feeding', 'caring for': παω in Greek (pronounce "paoh").
Words like pater (papa, father), pais (child/boy - as in paedophilia), pathos, pastor (shepherd - from the Latin pasco, to lead a herd or flock), passio (suffering), passion, the Latin panis (bread), the French pain (bread) and even pasta all derive from the same root PA. And... so do the English words food, fodder and feeding. (Via Old English, Old Scottish and Old Frisian words like fodian, fedan, fuoten, fodjan.)
The name of the planet Jupiter originally comes from the Greek name of the main God in the Greek pantheon: Ju-piter; it was originally Dios-Pater or God the provider.
The feeder - the father - Latin 'pater'
the fed - the child - Greek 'ped'
In Greek pathos (Latin passio) originally had the meaning of being fed, being cared for, being taken care off, undergoing.
Over time 'pathos' (as in pathology) also acquired the meaning of suffering, experiencing hunger, pain and anguish. In Latin the word passio (suffering) and passivus (passively undergoing) express the same meaning, hence the "Saint Matthew Passion" which has to do with the suffering of Christ before he died on the cross.
Interestingly, as to the word suffering, initially in English suffering did not necessarily have a pain connotation, it simply meant 'experiencing' or 'letting it be' as in the sentence Jesus used when he said, "Suffer the little children." *
The interpretation of pathos connoting feeling and sensation is apt, but when the interpretation includes experiencing an extra dose of passionate energy, it is even more apt.
The original self (the higher or inner self) uses pathos as feeling, experience, sensation, undergoing the experience of being energized, being fed or supplied with energy - the stuff that is the origin of the original self.
Compassion or sympathy (roughly equated with empathy in English) is what Bodhisattvas apply when they deal with beings who are energetically malnourished. A Bodhisattva helps the 'sufferer' to become re-energized.
'Pathos' proper is the sensation mechanism of the higher or original self through the five senses or "the five skandhas" as Bodhisattva Avalokiteshvara calls it.
Compassion or loving kindness is the mechanism or gesture of healing... feeding...caring for...
Bodhisattvas feel pathos as unconditioned energy flowing through themselves (shakti, soma, amrita) feeding them, nurturing them, conditioning them to share it universally with anything and anybody around them... unconditionally!
* "And they brought young children to Him, that He should touch them: and His disciples rebuked those that brought them. But when Jesus saw it, He was much displeased, and said unto them, Suffer the little children to come unto Me, and forbid them not: for of such is the kingdom of God."~ Mark 10:13-14, see also Matthew 19:14.