Bokeh is a Japanese word that describes the background being out of focus when the subject is in focus. Very important for portraits as you don't want the background to take any attention away from the subject. However for something like landscapes you would probably not want bokeh effects, so you would use different settings than you would for portraits.
Uh oh, the spread of urban legend...let us stop a falsehood soon enough to not misinform OP permanently! Unfortunately this particular urban legend is the STD of photography...it is widely communicated to others! But, like most STDs we can stop further spread of this one.
- What is within the Depth of Field is 'in focus'
- What is outside the Depth of Field is 'out of focus blur'
- The Out of Focus blur has a certain characteristic look, which is dependent upon the lens which is in use, and that 'characteristic' is called (correctly) 'bokeh'
- 'Bokeh' is NOT what you call 'out of focus blur'.
Many will argue vehemently that I am WRONG...let me call Zeiss to testify about the truth...
To quote a Zeiss paper, Depth of Field and Bokeh Carl Zeiss, Camera Lens Division, March 2010...
"Bokeh – properties of blurriness
"It is therefore perfectly right that the Japanese word “bokeh“ is used around the world as a collective term for all attributes of blurring."