What is the X in X-mas?
abbreviation for personal computer is from 1978; abbreviation for politically correct is by 1990.
first attested in prevailing current sense 1970; abbreviation P.C. is from 1986.
[T]here is no doubt that political correctness refers to the political movement and phenomenon, which began in the USA, with the aim to enforce a set of ideologies and views on gender, race and other minorities. Political correctness refers to language and ideas that may cause offence to some identity groups like women and aims at giving preferential treatment to members of those social groups in schools and universities. [Thuy Nguyen, "Political Correctness in the English Language,"2007]
Latin post cibum (after meals)
An abbreviation for “politically correct.” It refers to social, political, and educational changes designed to redress historical injustices in areas such as race, gender, ethnic background, and sexual orientation: “Haven't you read the latest directive on p.c. language? Please refer to our colleagues as ‘women,’ not ‘ladies’ or ‘girls.’” The phrase and abbreviation, which also appears as PC, both debuted in the late twentieth century.