| acquired characteristic |
a change in the structure or function of a living organism that is caused by environmental factors and may not be transmitted genetically. |
| Acremonium |
the genus of fungi, formerly known as Cephalosporium, from which the antibiotic cephalosporin was originally isolated. Several species may cause disease in humans, esp. pneumonia. |
| add-on |
an optional item that may be bought in addition to a main item to supplement or improve it. [1/2 definitions] |
| adenosine |
an organic compound that is made up of adenine and ribose and found in nucleic acids, and that may be obtained as a white crystalline powder through the hydrolysis of yeast. |
| ad libitum |
at one's pleasure (used as a musical direction to indicate that a section so marked may be varied, improvised upon, or omitted, as the performer wishes, or as a stage direction to indicate that the performer may improvise). |
| AIDS-related complex |
a condition characterized by enlargement of the lymph nodes that may be an early sign of AIDS. |
| air letter |
a sheet of very lightweight paper that may be folded into an envelope for mailing abroad; aerogramme. [1/2 definitions] |
| allotrope |
one of several forms in which a chemical element may exist. |
| amen |
thus it is; may it be so (used at the end of a prayer or statement to express agreement or approval). [1/3 definitions] |
| American dream |
the American ideal that any man or woman may obtain material wealth, equality, freedom, and the like. |
| arbovirus |
any of a number of viruses that are transmitted by certain blood-sucking arthropods such as mosquitoes and ticks and that may cause encephalitis, yellow fever, or dengue fever. |
| asymptomatic |
not showing any symptoms of a disease (usu. used in reference to an individual who does, in fact, have the disease and may or may not be a carrier). |
| at ease |
in the military, a standing position in which soldiers may relax but not leave formation or talk. [1/2 definitions] |
| auld lang syne |
(cap.) a Scottish song traditionally sung at midnight on New Year's Eve in many English-speaking countries. The contemporary melody is also popular in many other countries but may be sung on different occasions and with different lyrics. [1/2 definitions] |
| bacterium |
any of a large group of one-celled microscopic organisms of various shapes that are often agents of fermentation and putrefaction and that may cause disease. |
| balloon |
a bag made of rubber or other light, strong material that may be filled with air or helium and used as a decoration or toy. [1/8 definitions] |
| banner |
a rectangular space that may occupy the top, bottom, or side edge of a webpage and is typically used for announcements and advertisments. [1/6 definitions] |
| belay |
in mountain climbing, a secure projection such as a rock, tree, or the like, around which a rope may be run or fastened. [1/6 definitions] |
| bicycle pump |
a small pump used to inflate bicycle tires, esp. a hand-held pump that may be attached to a bicycle frame when not in use. |
| black sheep |
one who differs from and is often an embarrassment or disgrace to his or her family or group. This may be be due to this person's disreputable behavior, lack of worldly success, or difference in belief or point of view from that of the group. |
| blog |
shortened form of "Web log," an online journal that may be personal or topical, in which the author makes regular entries that appear in reverse chronological order and can be read by the general public. [1/2 definitions] |