AIR - The atmospheric substance above the surface of the earth which animals breathe, formerly considered to be a single substance, one of the four basic elements of ancient philosophy and one of the five basic elements of Eastern traditions.
ART - Human effort to imitate, supplement, alter, or counteract the work of nature.
RAT - A medium-sized rodent belonging to the genus Rattus.
TAR - A black, oily, sticky, viscous substance, consisting mainly of hydrocarbons derived from organic materials such as wood, peat, or coal.
VIA - A main road or highway, especially in ancient Rome. (Mainly used in set phrases, below.).
VAT - A large tub, such as is used for making wine or for tanning.
TRIVIA - Insignificant trifles of little importance, especially items of unimportant information.