Uncle Nick's has a cozy aura - just the kind of restaurant you look for in an older, established neighborhood like Cherrydale in Arlington.

A friend of ours discovered Uncle Nick's as a lunch spot and urged us to try it for dinner. So off we set one evening down Lee Highway. We discovered our destination via a large sign on Lee, which was fortunate, since Uncle Nick's entrance is on Quincy Street.

Being on a corner, the restaurant is a wedge-shaped affair, because as all northern Virginians know, no two streets in Arlington intersect at right angles. But Uncle Nick has made the most of his small, oddly shaped setting for an eatery. Comfortable booths line the walls, and the ceiling is almost festooned with the greenery of hanging baskets - mostly ferns and philodendron.

We were shown to our seats by a friendly hostess who turned out to be Uncle Nick's wife, Janna Georges. She, her husband and Essy Saedi have owned the restaurant two years, she told us.

Our waitress came promptly for our orders and brought some bread in a basket to stave off starvation. The two boys each ordered a soft drink.

The menu at Uncle Nick's offers simple fare, for the most part, although the night we ate there, duck a l'orange was on the menu for $5.95. Other choices included " Uncle Nick's Fried Chicken," $4.45, calves' liver and onions, $6.75, shish kabob, $6.25 and sirloin steak, $7.45. There are a few seafood selections - sole, $5.25, and brook trout, $6.25, among them.

There is a limited children's menu - two items, hamburger or fried chicken, each at $2.959

Our 3-year-old ordered the latter and was qyite pleased since his tastes conform exactly to what most restauranteurs imagine children prefer. Our 6-year-old goourmet, however, would have nothing to do with the children's fare, and insisted on ordering crab cakes, at $6.455.

I'm always a little skeptical of crab cakes in strange surroundings, but these arrived, the pair of them, steaming, chock full of crab meat and deliciously seasoned.

My husband chose the shish kabob for $6.25, made with beef, which he declared done perfectly. I ordered one of the specials, the fresh sea trout, for $6.25. It seemed to, in fact, be fresh, and it was happily not overdone as restaurant fish so often is. The fish was delicately seasoned with parsley, lemon and just a hint of thyme. The chef has the perfect touch with herbs at Uncle Nick's.

Uncle Nick's also offers sandwiches - reubens, burgers and clubs - that we didn't try. Most are in the $2.50 to $3.50 range.

The meal's only disappointment was my baked potato (The children had theirs fried, and my husband's shish kabob came in with rice). It arrived swaddled in tin foil and, alas, was dry and pasty inside. The salad of crisp greens more than made up for it, however.

We skipped dessert, which ranged from cheese cake at $1.25 to apple pie for 95 cents. It was just as well, since Georges keeps a basket of candy bars under the cashier's table, and she generously dolesthem out to her sub-teen coustomers, whom she obviously enjoys.

The bill for this tasty meal in a friendly place was $25.71, including tip. Uncle Nick's Family Restaurant

4030 Lee Highway, Arlington, 525-7899.

Atmosphere: Comfortble, friendly and unhurried.

Price: Reasonable.Complete dinners are in the $5 to $7 range. Children's menu items are $2.95.

Hours: 11 a. m. to 11 p. m. Monday through Saturday. Sunday 11 a. m. to 9 p.m.

Credit cards: Visa, Master Charge.

Special Facilities: Parking alongside the restaurant. Wheelchairs might have trouble negotiating the front door. Booster seats and high chairs are available for small children.