Definitions 

Street photography, also sometimes called candid photography, is photography conducted for art or enquiry that features unmediated chance encounters and random events within public places. Street photography can focus on people and their behavior in public.

A candid photograph is a photograph captured without creating a posed appearance. This can be achieved in many ways, for example when the subject is in motion, by surprising the subject, by not distracting the subject during the process of taking photos etc.

Articles about street photography

http://erickimphotography.com/blog/the-ultimate-beginners-guide-for-street-photography/

https://digital-photography-school.com/ultimate-guide-street-photography/

Quotes

"if your photos aren't good enough, then you're not close enough" - Robert Capa

"It is more important to click with people than to click the shutter" - Alfred Eisenstaedt

Threshold concept #7

The meanings of photographs are never fixed, are not contained solely within the photographs themselves and rely on a combination of the viewer's sensitivity, knowledge and understanding, and the specific context in which the image is seen.