Tarmac (short for tarmacaam, a portmanteau for tar-penetration macadam) is a type of highway surface, pioneered by John Loudon McAdam in around 1820. Strictly speaking, Tarmac refers to a material patented by Edgar Purnell Hooley in 1901. The term is also used, with varying degrees of correctness, for a variety of other materials, including tar-grouted macadam, Tarvia, bituminous surface treatments and even modern asphalt concrete.