Adjective

(en adjective)

Well grounded or justifiable, pertinent.

*{{quote-magazine, year=2012, month=March-April

, author=(Jan Sapp) , title=Race Finished , volume=100, issue=2, page=164 , magazine=(American Scientist) citation , passage=Few concepts are as emotionally charged as that of race. The word conjures up a mixture of associations—culture, ethnicity, genetics, subjugation, exclusion and persecution. But is the tragic history of efforts to define groups of people by race really a matter of the misuse of science, the abuse of a valid biological concept?}}

I will believe him as soon as he offers a valid answer.

Acceptable, proper or correct.

A valid format for the date is MM/DD/YY.

Do not drive without a valid license.

Related to the current topic, or presented within context, relevant.

(logic) Of a formula or system: such that it evaluates to true regardless of the input values.

(logic) Of an argument: whose conclusion is always true whenever its premises are true.

An argument is valid if and only if the set consisting of both (1) all of its premises and (2) the contradictory of its conclusion is inconsistent.

Adjective

(en adjective)

Of a regularly occurring, dependable nature.

The consistent use of Chinglish in China can be very annoying, apart from some initial amusement.

He is very consistent in his political choices: economy good or bad, he always votes Labour!

Compatible, accordant.

* {{quote-magazine, date=2012-01

, author=Steven Sloman , title=The Battle Between Intuition and Deliberation , volume=100, issue=1, page=74 , magazine= citation , passage=Libertarian paternalism is the view that, because the way options are presented to citizens affects what they choose, society should present options in a way that “nudges” our intuitive selves to make choices that are more consistent with what our more deliberative selves would have chosen if they were in control.}}

(logic) Of a set of statements, such that no contradiction logically follows from them.