British English Dictionary V4 for Firefox, Thunderbird, and SeaMonkey. A rigorously maintained, community-driven resource for accurate British English spelling. 📢 Update: As of March 2025, this dictionary fully aligns with modern -ise verb spellings (e.g., “organise”). For specific -ise/-ize variants, some verbs, and words MAY be missing or incorrectly included. 🔗 WEBSITES Website: https://proofingtoolgui.org (Proofing Tool GUI) Website: https://github.com/marcoagpinto/aoo-mozilla-en-dict (GitHub) Website: https://linkedin.com/in/marcoagpinto (LinkedIn) 🌟 Key Features: • 140 000+ words added since 2013 (updated to V4); • Prioritises Oxford, and Collins dictionaries as primary sources; • Supports both modern and literary vocabulary; • Compatible with Commonwealth/European English variants. 🔍 Inclusion Rules: 1. Words verified in ≥2 authoritative sources (e.g., Oxford + Collins) (except proper nouns); 2. Archaic terms allowed only if they don't conflict with modern usage; 3. U.S. spellings are retained when they are widely adopted into British English (e.g., “movie”), as validated by trusted sources like Oxford or Collins. The dictionary's U.S. origins explain why many U.S. words come from it. 📥 Installation: 1. Firefox/Thunderbird 115+ (ESR): Install directly via Mozilla Add-ons; 2. Legacy Firefox/Thunderbird (v59 or below): • Download the .xpi file from GitHub https://github.com/marcoagpinto/aoo-mozilla-en-dict • Drag'n'drop the downloaded .xpi file into the Extensions/Dictionaries windows. 3. Enable via right-click in an editable text area: “Languages” → “English (United Kingdom)”. 📚 Full guide: https://proofingtoolgui.org/en_installing.html 🛠 Developer Commitment: • 15+ years of continuous updates; • Funded personally (hosting, Oxford Premium Account access, domains); • Open-source collaboration via GitHub; • Proofing Tool GUI framework (proofingtoolgui.org) enables transparent word validation. ❓ FAQ Highlights: • Why include “movie”? → FAQ #7 https://proofingtoolgui.org/faq.html#7 • Reporting issues → FAQ #4 https://proofingtoolgui.org/faq.html#4 • Changelog → https://proofingtoolgui.org/en_GB_CHANGES.txt 🤝 Community-Driven: This project thrives on user input. If you find: • Missing Oxford/Collins words → E-mail/GitHub submissions welcome; • U.S. spellings needing removal → Provide dictionary citations; • Technical issues → Contact via e-mail/GitHub. ℹ Ethical Notes: • No AI/automated scraping – all entries manually verified; • Archaic terms cautiously included for literary users; • Hosting costs covered privately. This dictionary serves everyone equally – students, professionals, writers, and non-native speakers. Your feedback ensures it remains the most reliable free British English resource available. NOTICE: I have been publicly criticised for my GB dictionary, even in front of other developers. They only point out flaws instead of suggesting new words or corrections. There are millions of words, and I can't manage them all alone. This project is very serious. I spend hundreds of EUR every year on web hosting, domains, and a premium Oxford Dictionaries account so that everyone can enjoy quality work for free. I am a disabled person and open-source is almost all I have left in life.