flowchart vs flow diagram

flowchart and flow diagram both are nouns.

Word	Noun	Adjective	Verb	Adverb
flowchart	Yes	No	No	No
flow diagram	Yes	No	No	No

As nouns, flowchart and flow diagram are synonyms defined as:

flowchart and flow diagram: a diagram of the sequence of operations in a computer program or an accounting system

Other synonyms of flowchart include flow chart, flow sheet.

flowchart (noun)	flow diagram (noun)
a diagram of the sequence of operations in a computer program or an accounting system	a diagram of the sequence of operations in a computer program or an accounting system