There are no rules or standards for the information in box 14, or for any abbreviations that are used. The employer can put pretty much whatever they want in that box. If there is something you don't understand, you have to ask the employer to explain it. In general, you should enter it in TurboTax exactly as it appears on your W-2.
(I would guess that "LTD" stands for long-term disability. It's probably money that was deducted from your pay to pay for long-term disability insurance. If that's what it is, it's just for your information. It does not affect your tax return, but enter it in TurboTax anyway. Of course, this is just my guess. If you want to be certain, ask your employer what it is.)