a line of text after the address on a piece of correspondence, directing it to a particular person or department.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use attention line in a sentence
Some experiments have indicated, however, that a well-written attention line is fully as effective as an average illustration.
The attention-line CD is at the point that makes the upper section a “golden rectangle.”
Obviously the chain of reasoning must start from the attention line.