An ambiance is the mood or setting of a place. You might like the ambiance of a certain restaurant because the lighting and decor makes you feel comfortable and happy.
Ambiance is pronounced "AHM-bee-ahns." Most places have an ambiance made up of whatever sights, smells, sounds, and even sensations or textures fill the space. A fancy French restaurant gets its ambiance from the candlelight and chic black outfits worn by the wait staff while the diner off the highway might have a funky, retro ambiance because of its 1950s counter and jukebox full of golden oldies.