converse

from The Century Dictionary.

• To keep company; associate; hold intercourse: followed by with.
• To talk informally with another; have free intercourse in mutual communication of opinions and sentiments by spoken words; interchange thoughts by speech; engage in discourse: followed by with before the person addressed, and on before the subject.
• To have sexual commerce. Guardian.
• noun Acquaintance by frequent or customary intercourse; familiarity: as, to hold converse with persons of different sects, or to hold converse with terrestrial things.
• noun Conversation; familiar discourse or talk; free interchange of thoughts or opinions.
• noun Sexual commerce.
• Turned about; transposed; reciprocal.
• noun A part answering or corresponding to another, but differing from it in nature and required to make it complete; a complement; a counterpart: as, the hollows in a mold in which a medal has been cast are the converse of the parts of the medal in relief. [Converse is often used incorrectly in the sense of reverse— that is, the opposite, the contrary.
• noun In logic: Either of the pair of relations which subsist between two objects, with reference to each other: thus, the relation of child to parent is the converse of the relation of parent to child. One of a pair of propositions having the same subject and predicate or antecedent and consequent, but in the reversed order.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Logic) A proposition which arises from interchanging the terms of another, as by putting the predicate for the subject, and the subject for the predicate.
• noun (Math.) A proposition in which, after a conclusion from something supposed has been drawn, the order is inverted, making the conclusion the supposition or premises, what was first supposed becoming now the conclusion or inference. Thus, if two sides of a sides of a triangle are equal, the angles opposite the sides are equal; and the converse is true, i.e., if these angles are equal, the two sides are equal.
• adjective Turned about; reversed in order or relation; reciprocal.
• intransitive verb To keep company; to hold intimate intercourse; to commune; -- followed by with.
• intransitive verb To engage in familiar colloquy; to interchange thoughts and opinions in a free, informal manner; to chat; -- followed by with before a person; by on, about, concerning, etc., before a thing.
• intransitive verb To have knowledge of, from long intercourse or study; -- said of things.
• noun Frequent intercourse; familiar communion; intimate association.
• noun Familiar discourse; free interchange of thoughts or views; conversation; chat.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb formal, intransitive To talk; to engage in conversation.
• noun ​(now literary) Familiar discourse; free interchange of thoughts or views; conversation; chat.
• adjective Opposite or reverse.
• noun The opposite or reverse.
• noun logic Of a proposition or theorem of the form: given that "If A is true, then B is true", then "If B is true, then A is true." equivalently: given that "All Xs are Ys", then "All Ys are Xs".

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective turned about in order or relation
• noun a proposition obtained by conversion
• adjective of words so related that one reverses the relation denoted by the other
• verb carry on a conversation