Definition of "circuit" []

• A closed, usually circular line that goes around an object or area. (noun)
• The region enclosed by such a line. See Synonyms at circumference. (noun)
• A path or route the complete traversal of which without local change of direction requires returning to the starting point. (noun)
• The act of following such a path or route. (noun)
• A journey made on such a path or route. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The circuit containing the battery, transmitter, and primary winding of the induction coil is called the _local circuit_."
• "The circuit of a complete pair of cords and plugs with their associated apparatus is called a _cord circuit_."
• "The advantages of putting the transmitter and the battery which supplies it with current in a local circuit with the primary of an induction coil, and placing the secondary of the induction coil in the line, have already been pointed out but may be briefly summarized as follows: When the transmitter is placed directly in the _line circuit_ and the line is of considerable length, the current which passes through the transmitter is necessarily rather small unless a battery of high potential is used; and, furthermore, the total change in resistance which the transmitter is capable of producing is but a small proportion of the total resistance of the line, and, therefore, the current changes produced by the transmitter are relatively small."