AHA - An exclamation of understanding, realization, invention, or recognition.
ANT - Any of various insects in the family Formicidae in the order Hymenoptera, typically living in large colonies composed almost entirely of flightless females.
ART - Human effort to imitate, supplement, alter, or counteract the work of nature.
HAT - A covering for the head, often in the approximate form of a cone or a cylinder closed at its top end, and sometimes having a brim and other decoration.
RAN - Simple past of run.
RAT - A medium-sized rodent belonging to the genus Rattus.
TAN - A symbol of the trigonometric function tangent.
TAR - A black, oily, sticky, viscous substance, consisting mainly of hydrocarbons derived from organic materials such as wood, peat, or coal.
TAX - Money paid to the government other than for transaction-specific goods and services.
AAH - Indication of amazement or surprise or enthusiasm.
THAN - (usually used with for) Because; for.
RANT - A criticism done by ranting.
HART - A male deer, especially the male of the red deer after its fifth year.
TAXA - Plural form of taxon.
ANTHRAX - An acute infectious bacterial disease of herbivores, especially sheep and cattle. It can occur in humans through contact with infected animals, tissue from infected animals, or high concentrations of anthrax spores, but is not usually spread between humans. Symptoms include lesions on the skin or in the lungs, and it is often fatal.