De facto racial discrimination and segregation in the United States during the 1950s and 1960s was simply discrimination that was not segregation by law (de jure).
Jim Crow laws, which were enacted in the 1870s, brought legal racial segregation against black Americans residing in the American South. These laws were legally ended in 1964 by the Civil Rights Act of 1964.
Continued practices of expecting black people to ride in the back of buses or to step aside onto the street if not enough room was present for a white person and "separate but equal" facilities are instances of de facto segregation. The NAACP fought for the de jure law to be upheld and for de facto segregation practices to be abolished.
Public schools in any region of the US may be de facto racially segregated (or nearly so) simply because they are in neighborhoods whose residents are all, or nearly all, of one race (such as urban ghettos or conversely, affluent suburbs).
This is opposed to de jure segregation, which prevailed in the American South and border states through the 1960s. Under de jure segregation, the law provided entirely separate schools for black and white students, which they legally had to attend, despite in many cases actually living closer to a school designated for the other race. In many cases, the schools for black students were older, had fewer resources of all kinds, and paid their teachers less than in white schools.
A de facto standard is a standard (formal or informal) that has achieved a dominant position by tradition, enforcement, or market dominance. It has not necessarily received formal approval by way of a standardization process, and may not have an official standards document.
Technical standards are usually voluntary, like ISO 9000 requirements, but may be obligatory, enforced by government norms, like drinking water quality requirements. The term "de facto standard" is used for both: to contrast obligatory standards (also known as "de jure standards"); or to express a dominant standard, when there is more than one proposed standard.
In social sciences, a voluntary standard that is also a de facto standard, is a typical solution to a coordination problem.
Several countries, including Australia, Japan, the United Kingdom, and the United States, have a de facto national language but no de jure official national language.
Some countries have a de facto national language in addition to an official language. In Lebanon and Morocco the official language is Arabic, but an additional de facto language is French. In New Zealand, Maori and New Zealand Sign Language are de jure official languages, while English is a de facto official language.
Russian was the de facto official language of the central government and, to a large extent, republican governments of the former Soviet Union, but was not declared de jure state language until 1990. A short-lived law effected April 24, 1990, installed Russian as the sole de jure official language of the Union.