What Is The Logic Of Word "Physics"?

Physics is the study of physical phenomenons. That is why it is termed as "physics". The word 'Physics' is the Greek word 'Φυσική' (pronounced like Fee-see-kee)

This word means natural in greek. Study of the natural science is called as physics.

As an adjective, 'Φυσική' characterizes what is related to the noun 'Φύσις' = 'Nature'.

No doubt, physics is the science of nature.

Taimur is good with his etymology, however, I would like to point out also something else. Physics if you take away the (s) and add (al) what do you get? PHYSICAL! Physics is not the study of nature. It is the study of natural laws, supreme natures etc. Greek and Latin had multiple meanings for words depending on context. So basically the logic of physics is that it is the study of the rules and interplay of the physical universe. Physics does not do much to describe or define, categorize or show how leaves or grass grow or how a bug moves. It does explain the PHYSICS of how that ant is able to carry 10 times it's own body weight.