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

puzzle-icon

NEED HELP SOLVING A CROSSWORD PUZZLE?

Go to our Crossword Puzzle Solver and type in the letters that you know, and the Solver will produce a list of possible solutions.

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

sis·ter (sĭstər)
Share:
n.
1. A female having the same parents as another or one parent in common with another.
2. A girl or woman who shares a common ancestry, allegiance, character, or purpose with another or others, specifically:
a. A kinswoman.
b. A woman fellow member, as of a sorority.
c. A fellow woman.
d. A close woman friend or companion.
e. A fellow African-American woman or girl.
f. A woman who advocates, fosters, or takes part in the feminist movement.
3. Informal Used as a form of address for a woman or girl.
4. Abbr. Sr.Ecclesiastical
a. A member of a religious order of women; a nun.
b. Used as a form of address for such a woman, alone or followed by the woman's name.
5. Chiefly British A nurse, especially the head nurse in a ward.
6. One identified as female and closely related to another: "the sisters Death and Night" (Walt Whitman).
7. Architecture A beam or other structural member affixed to another as a supplementary support.
adj.
1. Related by or as if by sisterhood; closely related: sister ships; sister cities.
2. Genetics Of or being one of an identical, related, or homologous pair: sister chromatids.
tr.v. sis·tered, sis·ter·ing, sis·ters
Architecture To affix a beam or other structural member to (another) as a supplementary support.

[Middle English, partially from Old Norse systir and partly from Old English sweostor; see swesor- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. 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.

This website is best viewed in Chrome, Firefox, Microsoft Edge, or Safari. Some characters in pronunciations and etymologies cannot be displayed properly in Internet Explorer.