<p><strong>noun</strong></p><ul><li>A single thing or person.</li><li>Any group of things or persons regarded as an entity: They formed a cohesive unit.</li><li>One of the individuals or groups that together constitute a whole; one of the parts or elements into which a whole may be divided or analyzed.</li><li>One of a number of things, organizations, etc., identical or equivalent in function or form: a rental unit; a unit of rolling stock.</li><li>Any magnitude regarded as an independent whole; a single, indivisible entity. Also called dimension.</li><li>Any specified amount of a quantity, as of length, volume, force, momentum, or time, by comparison with which any other quantity of the same kind is measured or estimated.</li><li>The least positive integer; one. Also called unit's place.</li><li>(In a mixed number) The position of the first digit to the left of the decimal point.</li><li>(In a whole number) The position of the first digit from the right of the decimal point.</li><li>A machine, part, or system of machines having a specified purpose; apparatus: a heating unit.</li><li>Education. A division of instruction centering on a single theme.</li><li>Military. An organized body of soldiers, varying in size and constituting a subdivision of a larger body.</li><li>Medicine/Medical. The measured amount of a substance necessary to cause a certain effect; a clinical quantity used when a substance cannot be readily isolated in pure form and its activity determined directly.</li><li>The amount necessary to cause a specific effect upon a specific animal or upon animal tissues.</li><li>Mathematics. An identity element. An element in a group, ring, etc., that possesses an inverse.</li></ul>