| acid |
in chemistry, any of a group of substances that usu. dissolve in water, have a sour taste, and form salts in reaction with bases. (Cf. base.) [6 definitions] |
| acid rain |
rain that has high acidity because of being mixed with pollutants such as vehicle exhausts and residues from burning of fossil fuels for energy or from chemical manufacturing. |
| acknowledge |
to admit or recognize the truth, existence, fact, or validity of. [4 definitions] |
| acknowledgment |
the act of acknowledging, or the fact of being acknowledged. [2 definitions] |
| acne |
a skin disorder caused by inflammation of the oil glands, resulting in pimples, usu. on the face. |
| acorn |
the fruit of the oak tree, having a smooth, ovoid nut partially enclosed by a rough, cuplike base. |
| acoustic |
having to do with sound or the science of sound, or with the sensation and organs of hearing. [3 definitions] |
| acoustics |
(used with a sing. verb) the branch of science dealing with the physics of sound. [2 definitions] |
| acquaint |
to introduce, or to make familiar or accustomed to (usu. fol. by "with"). [2 definitions] |
| acquaintance |
a person one has met but does not know well. [3 definitions] |
| acquire |
to come to possess, esp. gradually over time. [2 definitions] |
| acquit |
to clear (someone) of a charge or accusation, as in a court of law. [3 definitions] |
| acre |
a unit of area equal to 43,560 square feet or 4,047 square meters, used in measuring land. [2 definitions] |
| acreage |
an area or areas of land measured in acres; acres collectively. [2 definitions] |
| acrobat |
a person who performs feats of balance and physical dexterity. |
| acrobatic |
having to do with acrobats or feats of balance and skill. |
| acronym |
a type of abbreviation used as a word and pronounced as a word. An acronym is formed by combining the initial letters (or initial parts) of a string of words. The pronunciation of an acronym is based on the typical rules of pronouncing words in a language and is not made up of the sounds of the names of individual letters. The abbreviations "AIDS," "FICA," and "PIN" are acronyms, but the abbreviations "FBI," ATM," and "DVD" are not. |
| acrophobia |
an overwhelming fear of high places. |
| across |
from one side or end to the other of. [6 definitions] |
| acrylic |
of or characteristic of the corrosive liquid acrylic acid. [2 definitions] |
| act |
something done, esp. a specific instance; deed. [14 definitions] |