• assum. fin. -- assumable financing
• dk -- deck 
• gar -- garage (garden is usually abbreviated "gard")
• expansion pot'l -- may be extra space on the lot, or possibly vertical potential for a top floor or room addition. Verify actual potential by checking local zoning restrictions prior to purchase.
• fab pentrm -- fabulous pentroom, a room on top, underneath the roof, that sometimes has views
• FDR -- formal dining room (not the former president)
• frplc, fplc, FP -- fireplace
• grmet kit -- gourmet kitchen
• HDW, HWF, Hdwd -- hardwood floors 
• hi ceils -- high ceilings
• In-law potential -- potential for a separate apartment. Sometimes, local zoning codes restrict rentals of such units so be sure the conversion is legal first.
• large E-2 plan -- this is one of several floor plans available in a specific building
• lsd pkg. -- leased parking area, may come with an additional cost
• lo dues -- find out just how low these homeowner's dues are, and in comparison to what?
• nr bst schls -- near the best schools 
• pvt -- private
• pwdr rm -- powder room, or half-bath 
• upr- upper floor 
• vw, vu, vws, vus -- view(s) 
• Wow! -- better check this one out.

Resources:
"Real Estate's Ambiguous Language You Oughtta Understand," Glennon H. Neubauer, Ethos Group Publishing, Diamond Bar, CA; 1993.