Terminology

This page contains a list of terms used on this Web site. If you are looking for a definition and cannot find it here, please email with the information about what is missing.

Introduction

Most glass insulators are identified by their Consolidated Design (CD) number. This is a system that was developed by and is copyrighted by Mr. N. R. Woodward.

Most porcelain insulators are identified by their Universal Style, or U-number. This is a system that was developed by Jack Tod.

Common Terminology

The following items appear on most pages that show detailed information about the insulators:

Object Number: The object number is the Smithsonian Institution's unique identifier. If you have a question about a particular item that you see on this site, please use the object number in any correspondence.
Identifier: For items that have a CD number or a U-number, these numbers are used for the Identifier. If there is no CD or U-number, the Popular Name is usually used in this field.
Popular Name: This is the common name for the insulator. Many insulators do not have a popular name and this field will be blank or omitted.
Primary Embossing: Used mostly for glass insulators. It is generally the name of the manufacturer or the company for which it was made. The McDougald's Price Guide (see References) is organized by Primary Embossing. If the insulator contains no embossing, the Primary Embossing field will say "No Embossing". Some insulators will say "No Name", meaning there is some embossing on the insulator but usually only a mark or mold number or letter and no manufacturer's identification.
Material: Describes what the object is made of. Usually glass, porcelain, wood, etc.
Color: The color of the object. This can be somewhat subjective as there is no objective reference for color identification.
Base: The base of an insulator can be smooth, it can have drip points, it can have embossing, or several other variations. The type of base is indicated in the description. A more complete description of bases can be found in the McDougald's Price Guide.
Condition: Describes the overall condition of the object. The term "Very Near Mint" (abbreviated VNM) is often used for an insulator that is considered an excellent collector's specimen but may have some minor flaws. Otherwise, the flaws are usually described.
Specific Embossing: This identifies the exact embossing on the particular insulator. Embossing can occur in a number of different places on an insulator. See the Insulator Anatomy description. Abbreviations used here include: (FC) - front crown, (RC) - rear crown, (FS) - front skirt, (RS) - rear skirt. {MLOD} means mold line over dome.
Notes (or NIA Notes): These are notes made by the person who is cataloging the item. Sometimes these notes add historical or descriptive information that is not included on the Smithsonian's Catalog Card.
Catalog Card Description: Each object in the Smithsonian's collection has a catalog card that contains information about the object. The amount of detail contained on each catalog card is variable - sometimes it contains very little information and sometimes it contains useful information about where the piece came from or more details about what it is. This field will include information from the catalog card if it is useful.