General Terms:
askART Terms Glossary: Glossary Terms 'A': Art, Artists, Auction Records
International Commission on Illumination’s ILV: International Lighting Vocabulary (Standard CIE S 017/E:2011) : e-ILV | CIE
Museum of Modern Art Main Glossary: https://www.moma.org/learn/moma_learning/glossary
National Gallery, London Glossary of Art Terms: Glossary | Paintings | National Gallery, London
Tate Glossary of Art Terms: http://www.tate.org.uk/learn/online-resources/glossary
Essential Vermeer Glossary of Art Terms: Glossary of Art Terms
Will Kemp Art School Glossary of Oil Painting Terms: Oil Painting Terms - The Essential Guide for Beginners
Will Kemp Art School Glossary of Acrylic Painting Terms: The Ultimate Beginners Guide to Acrylic Painting Terms
Materials:
Glatfelter Glossary of Paper Terminology: Segments - Glatfelter Engineered Materials
Creative Glossary: Creative Glossary - Art Materials and General Art Terms Category
Art History:
Art History Archive Main Glossary: Art Glossary of Terms - Art Lexicon AA to AZ - The Art History Archive
Kahn Academy Art History Basics: https://www.khanacademy.org/humanities/art-history-basics/ah-glossary/a/art-history-glossary
Related Sciences:
Neuroscience Neuroscience, Fifth Edition Glossary: http://sites.sinauer.com/neuroscience5e/glossary.html
Eye Glossary: https://www.eyeglossary.net/
Polymer Glossary: Glossary
Conservation:
CAMEO: Conservation and Art Materials Encyclopedia Online : Main Page - CAMEO
Canadian Conservation Institute Glossary of Terms : http://canada.pch.gc.ca/eng/1439925170537
Fine Arts Conservancy Glossary for Paintings Glossary For Paintings | The Fine Arts Conservancy
Smithsonian Museum Conservation Institute : Museum Conservation Institute | Museum Conservation Institute
North Carolina Museum of Art - Primer for the Materials, Methods, and Techniques of Conservation: http://ncartmuseum.org/pdf/conservation-primer.pdf
University Library/University of Illinois Urbana-Champaign Glossary of Terms: Preservation Services – University of Illinois Library
Inside the Conservators Studio (by Gwen Spicer) A Glossary of Safe Materials for Storage: Inside the Conservator's Studio: Glossary of safe materials for storage
Printmaking:
University of Cork Glossary of Printmaking Terms: Printmaking Glossary of Art Terms
International Print Center, New York Glossary of Printmaking Terms:
http://www.ipcny.org/learn/glossary/Printindustry.com
Glossary of Printing and Graphic Terms: Glossary of Printing & Graphic Terms
USA OnCanvas.com Glossary of Giclee on Canvas and Fine Art Prints Terminology
USA, Glossary Of Picture Framing Terms
Wells & Drew The Printing Dictionary: http://wellsdrew.com/the-printing-dictionary/
Photography:
Nikon USA Glossary: Photography Glossary | Photography Terms & Video Terminology | Nikon
BHP Photo Glossary: https://www.bhphotovideo.com/explora/photography/tips-and-solutions/glossary-digital-photography-terms
Ritz Camera: http://www.ritzcamera.com/static?id=articles/research/photo-terms.html
Digital Photography Tips Glossary: Glossary of Digital Photography Terminology
George Eastman House Photographic Process Terms Glossary:
http://peib.dmu.ac.uk/about/glossary.php
Airbrush:
How to Airbrush Glossary: http://howtoairbrush.com/airbrush-terms-and-definitions/
Airbrush Guru: Airbrush Dictionary - Airbrush Guru
Airbrush 101 Glossary: http://www.axminster.co.uk/media/downloads/airbrush101-2011_mag_article.pdf