Hours: Open Sunday through Thursday 11 a.m. to 11 p.m., Friday and Saturday 11 a.m. to 12 a.m. MC, V, AE. No reservations. Prices: Most items $5.50 to $10. Complete dinner with wine or beer, tax and tip about $13 to $23 per person.

What's a watering hole? "A place where people gather socially," says Webster, but that's far too broad. No, the watering hole of the '80s, at least among restaurants, is a very specific animal, as different from other restaurants as a parrot is from pigeons.

The watering hole is a timid creature, given to imitating other members of its species. That makes it easy to spot. Look for 1)a restaurant with a person's name, preferably a little offbeat (Fritzbe's, Jasper's, Houston's) and often Irish to lend an authentic saloon aura (Hihan's, McDoogal's, Bennigan's); 2)a prominent bar against which patrons are usually pressed three deep; 3)lots of noise, most of it from the customers, who are forced to shout because everyone else is; 4)a dark, slick, carefully cultivated "old" look, achieved with brass, dark stained wood, planked floors, exposed brick, all dimly lit; 5)young, attractive well-rehearsed servers; 6)big portions; 7) moderate prices; and 8)uncomplicated, safe, mainstream food (burgers, omelettes, pasta, chili, barbecued ribs), usually with a little something for the splinter-group eaters -- vegetarians, dieters, chocoholics.

Houston's, an outpost of the M Street establishment (in turn, part of a national chain), is a purebred watering hole, so if you've read this far you should know what to expect. And, since it's become quite a success in a few short months on boom-town Rockville Pike (it seems to draw a profitable mixture of young singles and older suburbanites), you can also expect big crowds. And big waits. Allow 45 minutes on week nights, longer on weekends.

This is a handsome spread of a place, and, although located in a brand new office building, it's designed to give the impression of having been there forever. The menu is limited, even for a watering hole (no omelettes, no seafood, no pasta), but what's served is generally pretty good: burgers, salads, prime rib, steak, barbecue, a few Mexican-style creations.

The burgers are impressive: big, thick, nicely lean and generally grilled as ordered, with "medium rare" yielding a juicy, flavorful patty that's just pink inside. ("Generally" because quality control isn't perfect; one night we got a burger that had been allowed to dry out completely on the grill.) But the best way to taste the ground chuck isn't on a roll. Look instead for the Santa Fe platter, in which the meat is topped with soft grated cheese, chopped tomato and scallions. A perfect accompaniment is the iron skillet beans, smoky, peppery, enlivened with bits of pork.

Charcoal grilling is what's done best here, largely because it's done with restraint. Although there's an unmistakable hickory flavor and aroma to the meats, it's subtle enough so the flavor of the beef or chicken isn't lost. As any back-yard chef knows, the hardest part of barbecuing a chicken is getting the meat -- particularly the breast -- to remain moist. Houston's seems to have it down pat, with nicely marinated breast fillets basted on the grill in a properly vinegary, not-too-sweet sauce. Look particularly for "chicken and friends," the barbecued chicken topped with smoked ham and a bit of melted cheese. They certainly have the barbecued ribs mastered, too, a generous platter of 10 good-size ribs for $9.95, the meat thinly crusted outside and succulent within, cooked so it's just ready to fall off the bone.

If barbecue isn't your bag, consider chicken tenders (available in appetizer and entree portions), strips of succulent white meat well frie in a golden-light, crusty batter. The rib eye steak is another very good product of the grill, a piece of meat with real texture and juiciness; if it's not as flavorful as we would have hoped, that's more a reflection on the general state of beef these days than on Houston's. (Forget the Hawaiian steak, in which any natural flavor in the meat is strangled by a cloyingly sweet marinade.) If the steak was a qualified success, the prime rib was an unqualified loser, the meat's dryness and lack of texture (let alone flavor) undisguised by the accompanying cup of "au jus." Too bad, because it would have been a good buy at $7.95 with warm french bread and potato. Speaking of which, we found the baked potatoes reliably first rate but the french fries just as consistently poor -- dark brown, oily and unpleasant.

The chili is a good, solid rendition, with chunks of beef rather than hamburger (score one for the purists), enough pepper for punch (plus extra jalapeno if desired) and a nice cumin-smoke flavor that isn't compromised by too much sugar. For more than just an unadorned bowl, look for tortilla flats, in which the chili is served with tortilla chips, guacamole, cheese and diced vegetables. Salads are generous, but they're made dull by bland, oversweetened dressings.

There seem to be two desserts: an excellent, deep-flavored, generously nutted brownie served with a slab of vanilla ice cream, and a totally undistinguished apple cobbler with mushy, oversweet fruit. (The same stuff is available in a cinnamon-apple side order.) But look farther. Hidden away in the "extras" part of the menu is a sleeper of a dessert, a world- class milkshake so thick with with ice cream and egg that trying to suck it through a straw could cause you to slip a disc. At $1.75 it's a well-hidden bargain, too.

Houston's is one of the better local watering holes, a nice- looking place with mainly good food at a fair price. If you understand watering holes as a species and know what to expect, you won't be disappointed. But remember, no one promised you culinary excitement, or tranquillity.