Definitions

1. noun

A letter; a written symbol or character used to represent a sound in writing.

“The email contained only two sentences and a single ltr.”

2. verb

To write or send a letter, especially a formal one.

“She ltr her boss to inform him of her resignation.”

3. abbreviation

Left-to-right (in computing and other contexts).

“LTR is a common abbreviation in digital design.”