LINE n. 3 definitions
Course of conduct, thought, occupation, or policy; method of argument; department of industry, trade, or intellectual activity. He is uncommonly powerful in his own line, but it is not the line of a first-rate man. Coleridge.
LOGIC n.
The science or art of exact reasoning, or of pure and formal thought, or of the laws according to which the processes of pure thinking should be conducted; the science of the formation and application of general notions; the science of generalization, judgment, classification, reasoning, and systematic arrangement; cor…