Thanks to Robert Joyce for uploading this helpful list of FREE reference materials to the Learning Librarians group on FB. I will be using it this year (note to self: saved as Word Doc in Library/TPT & Other Resources) with 2nd - 8th grades.
Almanac
http://www.shambles.net/pages/school/almanacs/
Information Please Almanac https://www.infoplease.com/almanacs
https://www.kidinfo.com/references/almanac.html
https://www.factmonster.com/almanac/fact-monster-almanac-search-page
https://www.thenauticalalmanac.com/
Fact Monster – Almanac https://www.factmonster.com/almanac/fact-monster-almanac-search-page
World Fact Book: https://www.cia.gov/library/publications/the-world-factbook/, which will have history, government, maps, etc. for countries around the world. Not everything in the almanac,
RefSeek's directory of the Web's top almanacs https://www.refseek.com/directory/almanacs.html
Atlas
World Atlas & Map Library https://www.factmonster.com/atlas
Atlases and Maps https://www.refseek.com/directory/atlas_maps.html
Atlapedia® Online http://www.atlapedia.com/
Free Atlases Found Online https://www.kidinfo.com/references/atlases.html
World atlas https://www.worldatlas.com/
United States Online Atlas https://www.worldatlas.com/webimage/countrys/namerica/us.htm
Owl and Mouse Online Atlas http://www.yourchildlearns.com/online-atlas.htm
Free Atlases Found Online https://www.kidinfo.com/references/atlases.html World Atlas & Map Library https://www.infoplease.com/atlas/world-atlas-map-library
Dictionary
Factmonster https://www.factmonster.com/dictionary
Dictionaries and Thesauri https://www.refseek.com/directory/dictionaries.html
Free Dictionary www.thefreedictionary.com
https://www.allwords.com/
http://www.livebinders.com/play/play?id=1905144
http://pdictionary.com/ picture dictionary
https://www.kidinfo.com/references/dictionaries.html
http://www.visualdictionaryonline.com/ This is a visual online dictionary providing copyright-free images matching dictionary definitions.
Merriam-Webster, dicionary https://www.merriam-webster.com/ scroll to bottom of home page for other dictionary types and options -à “ OTHER MERRIAM-WEBSTER DICTIONARIES”
Funk and Wagnalls dictionary http://www.funkandwagnalls.com/
Merriam-Webster's Word Central http://www.wordcentral.com/
Dictionary.com / check bottom of page for more options http://www.dictionary.com/
YourDictionary http://www.yourdictionary.com/
https://www.ahdictionary.com/
kids.wordsmyth.net dictionary free online student Picture Dictionary https://kids.wordsmyth.net/we/
https://en.oxforddictionaries.com/
Merriam-Webster's Learner's Dictionary
Kids.Net.Au http://dictionary.kids.net.au/
General dictionaries and glossaries indexed by the OneLook® search engine LONG LIST
http://onelook.com/browse.shtml
Visual Merriam-Webster http://www.visualdictionaryonline.com/
English language Dictionaries and Thesaurus
Bartleby http://www.bartleby.com/reference
Merriam-Webster www.m-w.com/netdict.htm
Visual Thesaurus http://www.visualthesaurus.com/
Fact Monster (for kids) www.factmonster.com/dictionary.html
Dictionary.com http://dictionary.reference.com/
Thesaurus.com http://thesaurus.reference.com/
The Free Dictionaryhttp://www.thefreedictionary.com/
NetLingohttp://www.netlingo.com/acronyms.php
International Language Dictionaries
Word Reference http://www.wordreference.com/
Language Dictionary and Translators http://www.word2word.com/dictionary.html
Online Spanish/English Dictionary http://www.spanishdict.com/
Online French/Spanish Dictionary http://www.frenchlinguistics.co.uk/dictionary/englishfrench/
Online Japanese/English Dictionary http://jisho.org/
Click on Spanish tab https://www.lexico.com/es
Medical Dictionaries
MedlinePlus Dictionary http://www.nlm.nih.gov/medlineplus/mplusdictionary.html
Mondofacto http://www.mondofacto.com/facts/dictionary
Medicine.net http://www.medterms.com/script/main/hp.asp
Free Medical Dictionary http://www.medterms.com/script/main/hp.asp
MedBioWorld http://www.medbioworld.com/MedBioWorld/TopicLinks.aspx?type=Reference%20Tools&&category=(All)&&concept=Medicine
Free Dictionary's Medical Dictionary http://medical-dictionary.thefreedictionary.com/
Scientific Dictionaries
Scientific Dictionaries http://www.science-books.net/dict.htm
Specialist Online Dictionary http://www.specialist-online-dictionary.com/scientific-dictionary.html
Scientific terms and Jargon http://dictionary.etacude.com/
Scientific Dictionary Indexhttp://lii.org/pub/subtopic/4504
Scientific resources and statistical formulae http://www.xycoon.com/i
Mnemonic dictionary www.mnemonicdictionary.com/
American Heritage Dictionary https://www.ahdictionary.com/
Lexico https://www.lexico.com/en click on dictionary tab
List on Shambles web site various titles http://www.shambles.net/pages/school/Encycl/
Idioms
Free Dictionary's Idioms dictionary http://idioms.thefreedictionary.com/
Thesaurus
Kids.Net.Au http://thesaurus.kids.net.au/
MERRIAM-WEBSTER THESAURUS https://www.merriam-webster.com/browse/thesaurus/a
Lexico https://www.lexico.com/en click on Thesaurus tab
Free Dictionary's Thesaurus http://www.freethesaurus.com/
Power thesaurus https://www.powerthesaurus.org/
Merriam-Webster's Word Central found in search box http://wordcentral.com/
Thesaurus.com http://www.thesaurus.com/
Thesaurus infoplease.com https://www.infoplease.com/thesaurus
Encyclopedia
Columbia Encyclopedia https://www.factmonster.com/encyclopedia
Encyclopedias https://www.refseek.com/directory/encyclopedias.html
Kids.Net.Au http://encyclopedia.kids.net.au/
Free Dictionary's Encyclopedia http://encyclopedia2.thefreedictionary.com/
Wikipedia (TheFreeDictionary.com mirror) http://encyclopedia.thefreedictionary.com/
Encyclopedia.com http://www.encyclopedia.com/
Encyclopædia Britannica https://www.britannica.com/
List on Shambles web site various titles http://www.shambles.net/pages/school/Encycl/
Biographical Dictionary and Bio sites
Who's Alive and Who's Dead http://www.whosaliveandwhosdead.com/
Married Biography site https://marriedbiography.com/
Inventor Biographies and Famous Inventions Facts https://www.kidinfo.com/american_history/inventors_inventions.html
Biographies of Famous People Both Past and Present https://www.biography.com/
Biographical Dictionary! https://www.s9.com/
Infoplease.com/people https://www.infoplease.com/people
Geographical Dictionary and Geography/Places sites
cia. world-factbook https://www.cia.gov/library/publications/the-world-factbook/
Kids' Zone https://www.cia.gov/kids-page
U.S. Gazetteer https://www.hometownlocator.com/
Getty Thesaurus of Geographic NamesR Online http://www.getty.edu/research/tools/vocabularies/tgn/index.html
Quotations
Quotation Resources https://www.kidinfo.com/references/quotations.html
Quotations Page http://www.quotationspage.com/
Quoteland http://www.quoteland.com/
Bartlett's Quotations https://www.bartleby.com/100/