use-icon

HOW TO USE THE DICTIONARY

To look up an entry in The American Heritage Dictionary of the English Language, use the search window above. For best results, after typing in the word, click on the “Search” button instead of using the “enter” key.

Some compound words (like bus rapid transit, dog whistle, or identity theft) don’t appear on the drop-down list when you type them in the search bar. For best results with compound words, place a quotation mark before the compound word in the search window.

guide to the dictionary

use-icon

THE USAGE PANEL

The Usage Panel is a group of nearly 200 prominent scholars, creative writers, journalists, diplomats, and others in occupations requiring mastery of language. Annual surveys have gauged the acceptability of particular usages and grammatical constructions.

The Panelists

open-icon

AMERICAN HERITAGE DICTIONARY APP

The new American Heritage Dictionary app is now available for iOS and Android.

scroll-icon

THE AMERICAN HERITAGE DICTIONARY BLOG

The articles in our blog examine new words, revised definitions, interesting images from the fifth edition, discussions of usage, and more.

100-words-icon

See word lists from the best-selling 100 Words Series!

Find out more!

open-icon

INTERESTED IN DICTIONARIES?

Check out the Dictionary Society of North America at http://www.dictionarysociety.com

pa·ram·e·ter (pə-rămĭ-tər)
Share:
n.
1. Mathematics
a. A constant in an equation that varies in other equations of the same general form, especially such a constant in the equation of a curve or surface that can be varied to represent a family of curves or surfaces.
b. One of a set of independent variables that express the coordinates of a point.
2.
a. One of a set of measurable factors, such as temperature and pressure, that define a system and determine its behavior and are varied in an experiment.
b. Usage Problem A factor that restricts what is possible or what results: "all the parameters of shelterwhere people will live, what mode of housing they will choose, and how they will pay for it" (New York).
c. A factor that determines a range of variations; a boundary: an experimental school that keeps expanding the parameters of its curriculum.
3. Statistics A quantity, such as a mean, that is calculated from data and describes a population.
4. Usage Problem A distinguishing characteristic or feature.

[New Latin parametrum, a line through the focus and parallel to the directrix of a conic : Greek para-, beside; see PARA-1 + Greek metron, measure; see -METER.]

para·metric (părə-mĕtrĭk), para·metri·cal adj.
para·metri·cal·ly adv.

Usage Note: The term parameter, which originates in mathematics, has a number of specific meanings in fields such as astronomy, electricity, crystallography, and statistics. Perhaps because of its ring of technical authority, people have applied parameter more generally in recent years to refer to any factor that determines a range of variations and especially to a factor that restricts what results from a process or policy. In this use, the word parameter is used to mean "the particular value of a parameter," and comes close to meaning "a set limit or boundary." For example, a budget can be thought of as a set of parameters that determine a range of activity, much like a set of mathematical parameters that establish the range of effects, or limits, of other variables. The sentence A budget is a framework that defines the financial parameters within which an organization operates was considered acceptable by 81 percent of the Usage Panel in our 2004 survey. Parameter is sometimes used incorrectly when it does not denote a range of variation, as if it were a technical-sounding synonym for characteristic. In 1988, 88 percent of the Usage Panel rejected the sentence The Judeo-Christian ethic is one of the important parameters of Western culture. In 2004, 77 percent rejected this same sentence, suggesting that familiarity has not bred tolerance of this usage.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
 

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.