street corner vs turning point

street corner and turning point both are nouns.

Word	Noun	Adjective	Verb	Adverb
street corner	Yes	No	No	No
turning point	Yes	No	No	No

As nouns, street corner and turning point are synonyms defined as:

Other synonyms of street corner include corner.

street corner (noun)	turning point (noun)
the intersection of two streets	the intersection of two streets
	an event marking a unique or important historical change of course or one on which important developments depend