a line of text after the address on a piece of correspondence, directing it to a particular person or department.
Origin of attention line
First recorded in 1920–25
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for attention line
Historical Examples of attention line
The attention-line CD is at the point that makes the upper section a “golden rectangle.”Practical English Composition: Book II.
Edwin L. Miller