LW

(electronics) Initialism of long wave.

Initialism of low water.

(linguistics) Abbreviation of loanword.

Initialism of letter writer — used as short-hand in comments to 'Dear Dorothy' advice columns. If there is more than one letter, then it's LWn, where n is the first/second etc. letter, such as LW1, LW2, and so on.

Initialism of left wing.