Logic, denotes a branch of method, opposite to analysis.

In the synthesis or synthetic method, we pursue the truth by reasons drawn from principles before established or assumed, and propositions formerly proved: thus proceeding by a regular chain, till we come to the conclusion. Such is the method in Euclid's Elements, and most demonstrations of the ancient mathematicians, which proceed from definitions and axioms, to prove propositions, &c., and from those propositions proved to prove others. This method we also call composition, in opposition to analysis or resolution. See Analysis.

Syphilis. See Medicine, No. 350.

Siphon. See Hydrodynamics. Some uncommon phenomena in nature may be accounted for upon the principles of the siphon; as, for instance, that of reciprocating springs. See Pneumatics, No. 373.