A number of abbreviations and conventions are used in writing a character which may be unfamiliar to new players. These will be understood in time; they are the jargon of the game. Every hobby or job has jargon, so does D&D.
AC - stands for armor class, and represents the statistical probability that a character will be hit by an attacker. In 3rd Edition, AC begins at 10 and goes up. A higher AC is a lower chance to be hit, so-called bonuses to AC are added from the "base AC". AC’s run from the worst of 10 up to 30 or more.
CHA - This refers to the one of the six ability scores, specifically Charisma.
CON - This refers to the one of the six ability scores, specifically Constitution.
DEX - This refers to the one of the six ability scores, specifically Dexterity.
DM - stands for Dungeon Master, the referee of the game; certain sections of the rules are for his eyes only, and he makes final decisions on the application of all rules.
DMG - Refers to the 3rd Edition Dungeon Masters Guide.
GP - Money uses several different coin types and designations which may vary from one milieu to the next, but most values here are stated in gold pieces, the equivalent of whole dollars, abbreviated "GP".
GPV - stands for "gold piece value", and may be used to indicate the value of certain items, such as gems.
HD - Hit Dice that a character has earned. In a PC, this equals the number of levels the character has earned in all classes.
HP - Hit points are abbreviated "HP" and represent the amount of injury a character can withstand before the injuries prove fatal; obviously, bonuses increase this number.
INT - This refers to the one of the six ability scores, specifically Intelligence.
NPC - stands "non-player character". A non-player character is any of the myriads of characters exclusively run by the referee.
PC - stands for "player character". A player character is one created and run by a player.
PHB - Refers the 3rd Edition Players Handbook.
STR - This refers to the one of the six ability scores, specifically Strength.
XP - Characters gain experience points, "XP" in this work for various successful tasks, usually overcoming monsters and collecting treasure. These xp advance the character through levels, increasing his abilities at all the things he learns as part of his class (profession).
WIS - This refers to the one of the six ability scores, specifically Wisdom.
d4, d8, d20, etc. - The letter "d" is used with numbers to indicate dice to be rolled. A number preceding the "d" is the number of specific dice to be rolled, while a number following the "d" is the number of sides each die should have. "d100", sometimes called percentile or percentage, is usually created by rolling 2d10, one of which is designated as representing the tens and the other the ones, with "00" representing 100 (d10’s are usually numbered as 0 through 9, but the 0 is usually treated as a 10 except in d100’s). Normally the dice are added together; adjustments to the die roll are indicated by various arithmetic symbols, most commonly "+" to add numbers (or additional differentiated dice) to a die roll, "-" to subtract in a similar way, and "x" to multiply the die roll by a constant.