A PRIORI

 Dictionary entry overview: What does a priori mean? 

• A PRIORI (adjective)
  The adjective A PRIORI has 2 senses:

1. involving deductive reasoning from a general principle to a necessary effect; not supported by fact

2. based on hypothesis or theory rather than experiment

  Familiarity information: A PRIORI used as an adjective is rare.

• A PRIORI (adverb)
  The adverb A PRIORI has 1 sense:

1. derived by logic, without observed facts

  Familiarity information: A PRIORI used as an adverb is very rare.

 Dictionary entry details 

• A PRIORI (adjective)

Sense 1

Meaning:

Involving deductive reasoning from a general principle to a necessary effect; not supported by fact

Context example:

an a priori judgment

Also:

analytic; analytical (of a proposition that is necessarily true independent of fact or experience)

deductive (involving inferences from general principles)

Antonym:

a posteriori (involving reasoning from facts or particulars to general principles or from effects to causes)

Sense 2

Meaning:

Based on hypothesis or theory rather than experiment

Similar:

theoretic; theoretical (concerned primarily with theories or hypotheses rather than practical considerations)

• A PRIORI (adverb)

Sense 1

Meaning:

Derived by logic, without observed facts

Antonym:

a posteriori (derived from observed facts)

 Context examples 

Non-parametric regression methods are aimed at describing a relationship between the dependent and independent variables without specifying the form of the relationship between them a priori.

(Non-Parametric Regression Method, NCI Thesaurus)