Basic trading terminology for beginners:

PM - Pre Market

AH - After Hours

DD - Due Diligence

PT - Price Target

SL - Stop Loss

HOD - High of the Day

LOD - Low of the Day

ATH - All Time High

PH - Power Hour

EOD - End of the Day

SSR - Short Sale Restriction

HH - Higher High

HL - Higher Low

LH - Lower High

LL - Lower Low

BTO - Buy to Open

BTC - Buy to Close

STO - Sell to Open

STC - Sell to Close

ATM - At the Money

OTM - Out of the Money

ITM - In the Money