Based on theoretical deduction only

• From theoretical deduction
• From logic rather than experience

Wiktionary Word definitions in Wiktionary
a. 1 (context logic English) Based on hypothesis rather than experiment. 2 self-evident, intuitively obvious 3 presumed without analysis 4 (context linguistics of a constructed language English) Developed entirely from scratch, without deriving it from ...

Wikipedia Word definitions in Wikipedia
A priori may refer to: A priori knowledge , a type of deduction justified by arguments of a certain kind A priori (languages) , a type of constructed language A priori estimate , a type of estimate for the size of a solution of a differential equation A ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1710, "from cause to effect" (a logical term, in reference to reasoning), Latin, literally "from what comes first," from priori , ablative of prior "first" (see prior (adj.)). Used loosely for "in accordance with previous knowledge" (1834).

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Regulative \Reg"u*la*tive\ (r?g"?*l?*t?v), a. Tending to regulate; regulating. --Whewell. (Metaph.) Necessarily assumed by the mind as fundamental to all other knowledge; furnishing fundamental principles; as, the regulative principles, or principles a ...

WordNet Word definitions in WordNet
adj: involving deductive reasoning from a general principle to a necessary effect; not supported by fact; "an a priori judgment" [ant: a posteriori ] based on hypothesis or theory rather than experiment adv : derived by logic, without observed facts [ant: ...