graph vs bar chart

graph and bar chart both are nouns.

Word	Noun	Adjective	Verb	Adverb
graph	Yes	No	Yes	No
bar chart	Yes	No	No	No

As nouns, bar chart is a hyponym of graph; that is, bar chart is a word with a more specific, narrower meaning than graph:

graph (noun)	bar chart (noun)
a visual representation of the relations between certain quantities, represented as points, plotted with reference to a set of axes	a chart with bars whose lengths are proportional to quantities
a visual display of information
a written symbol that is used to represent speech

graph (verb)	bar chart (verb)
represent by means of a graph
plot upon a graph