| abstraction |
an abstract or general idea, concept, or term. [1/4 definitions] |
| abuse |
a corrupt procedure or custom. [1/7 definitions] |
| Ac |
symbol of the chemical element actinium. |
| accession |
to catalogue in order of acquiring, as in a library or museum. [1/5 definitions] |
| accommodate |
to be or become adaptable; conform. [1/6 definitions] |
| accouterment |
(often pl.) one's outfit or equipment, esp. that of a soldier, exclusive of arms and uniform. [1/2 definitions] |
| accumulator |
an apparatus in a hydraulic or pneumatic system that stores and regulates the supply of fluid that provides pressure in the system. [1/3 definitions] |
| acid |
a scornful tone; sarcasm. [1/7 definitions] |
| acre |
a unit of area equal to 43,560 square feet, used to measure land. The acre is a standard unit of measurement in the United States and the United Kingdom. |
| actinide series |
the series of chemical elements, mostly synthetic and all radioactive, that have from eighty-nine to 103 protons per atom. |
| active |
used in grammar to describe a form of the verb that emphasizes the person or thing who performs the action. In the sentence "John ate the apple," the verb "ate" is in an active form. In the sentence "The apple was eaten by John," the verb is in a passive form. [1/2 definitions] |
| actor |
a person who performs in a play, a movie, or a radio or television program. |
| actress |
a woman or girl who performs in a play, a movie, or a radio or television program. |
| addend |
a number or amount added to another to form a sum. |
| add-on |
in computing, a supplementary program or piece of code written to alter, enhance, or extend the behavior of a main program. [1/2 definitions] |
| adenocarcinoma |
a malignant tumor formed in the glandular epithelium. |
| ad lib |
without preparation; in a spontaneous or improvised manner; ad libitum. |
| admirer |
a person who holds another person or a thing in high esteem. [1/2 definitions] |
| aeolian harp |
a musical instrument consisting of an open box with gut strings stretched across it that produce rising and falling sounds when wind passes over them. |
| aerodynamics |
(used with a sing. verb) a science that deals with the dynamics of air and other gases and with the forces acting on objects that move through them. |
| aeromechanics |
(used with a sing. verb) the science of air or gases in motion or equilibrium. |