Wirehaired Terrier is mostly a coat description. It's a common alternate name for the Wire Fox Terrier, an English breed developed in the 1700s and 1800s to bolt foxes from their dens, but listings also use it for wire-coated terrier mixes with Jack Russell, Border, Cairn or Schnauzer ancestry. What they share is a crisp, dense outer coat over a softer undercoat.
Most weigh roughly 13 to 25 pounds and stand 12 to 16 inches tall. They're bright, bold and curious, with classic terrier habits: barking, digging and chasing small animals. The wiry coat sheds little but needs weekly brushing and stripping or clipping every six to eight weeks. Because ancestry varies, a dog's actual size, energy and coat tell you more than the label does.