What’s in a name?

I’d like to draw distinctions between certain words used in the common martial arts vernacular by the uninitiated as well as the initiated that should be differentiated but most of the time are not. I’ve tried to be concise since each term has a wealth of literature available to them.

Taiji /Tai Chi - a philosophy predicated on the concept of change.

Taijiquan / Tai Chi Chuan- the physical manifestation of change.

Gongfu / Kung Fu - is the conscious determination and effort needed to understand and benefit from an activity. 

These terms have been used interchangeably and have diluted their intended meaning.

Hopefully these definitions, based solely on my understanding and reading, will generate discussion to either enhance or refute their premise.