https://www.macmillandictionary.com/
https://dictionary.cambridge.org/dictionary/english/
https://www.oxfordlearnersdictionaries.com/definition/english
https://www.ldoceonline.com/ (Longman)
https://youglish.com/ (pronunciation in context)
https://www.thefreedictionary.com/
https://www.dictionary.com/
https://www.diki.pl/
https://ling.pl/
https://pl.bab.la/slownik/
https://dictionary.reverso.net/english-polish/
https://languagetool.org/spellchecking-english