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1. a person who rules or commands
2. a strip of wood, metal, or other material, having straight edges graduated usually in millimetres or inches, used for measuring and drawing straight lines
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a tool used for geometric constructions, linear measurements, and calculations. A scale (or scales) is usually marked on a ruler, the value of which depend on the purpose of the ruler. For convenience, some rulers have reference data (magnitudes of physical values, multiplication tables) or special attachments. For instance, rulers used in cartography have a magnifying glass that can slide along the ruler. Rulers used for geometric construction and measurements include straightedges, try squares, and shaped rulers (for instance, officer’s and navigator’s protractors, stencils), as well as French curves. In industry, rulers are used to measure linear dimensions in specific units (for instance, points in printing). Rulers are also used in technology for various purposes. For instance, a shrink ruler serves to compare specified dimensions and actual dimensions (in foundries, textile production). A straightedge is used to check the linearity of generating lines or the smoothness of surfaces in manufactured articles. A tape measure is used for measuring large lengths or diameters. A ruled scale is used to change from one scale to another. A slide rule is used for mathematical computations.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


A graduated strip of wood, metal, or other material, used to measure lines or as a guide in drawing lines.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Guests arrive at the venue of the wedding reception of the three sons of His Highness Shaikh Mohammad Bin Rashid Al Maktoum, Vice-President and Prime Minister of the UAE and Ruler of Dubai.
This election process is in line with Malaysia's constitutional monarchy, where one of the nine Malay rulers or sultans will ascend the federal throne to become the Yang di-Pertuan Agong for a five-year term.
The prince revealed secret disputes among Emirati rulers, Abu Dhabi's involvement in money laundering cases and the UAE's sponsorship of Qatari royals in exile.
The special court had also asked the Interior Ministry to take action to revoke the Computerised National Identity Card (CNIC) and green passport of the former military ruler. The bench, formed in 2013, is hearing the case of imposition of extra-constitutional emergency by Musharraf in November 2007.
Results: What happened when you rubbed the ruler with each fabric?
Shaikh Mohammed bin Rashid and Shaikh Mohammed bin Zayed receive Rulers in Abu Dhabi.
HM the King and Fujairah Ruler discussed key issues featuring on the agenda of the 26th Arab Summit, extending greetings to the UAE leaders.
Hiebert (1984) suggests that this is because some students learn a procedure for reading a ruler without really understanding that the answer represents the distance between the beginning point and the end point of the object.
A transparent curved fashion ruler, sometimes called a Styling Design Ruler, aids in measuring and drawing curves.
Also present were the seven Crown Princes including Abu Dhabi Crown Prince HH Sheikh Mohammed bin Zayed Al Nayhan, Dubai Crown Prince Sheikh Hamdan bin Mohammed bin Rashid Al Maktoum, Sharjah Crown Prince and Deputy Ruler Sheikh Sultan bin Mohammed bin Sultan Al Qasimi, Ajman Crown Prince Sheikh Ammar bin Humaid Al Nuaimi, Fujairah Crown Prince Sheikh Mohammed bin Hamad bin Mohammed Al Sharqi, Umm Al Quwain Crown Prince Sheikh Rashid bin Saud bin Rashid Al Mualla and Ras Al Khaimah Crown Prince Sheikh Mohammed bin Saud bin Saqr Al Qasimi.