Where does “crossword” come from?

I can't write this etymology because the chain provided doesn't support "crossword" as a derivative. The chain traces from "worth" (Proto-Germanic wurdą) and "cros" (Old Irish) back through Latin crux and PIE roots, but these elements don't combine to form "crossword" in English. A valid etymology would need to show how "cross" + "word" developed, which this chain doesn't do. If you have the correct etymological chain for "crossword," I'd be happy to write the summary.

crossword (English): A word puzzle in which interlocking words are...

Definitions

  1. A word puzzle in which interlocking words are...

Ancestry of “crossword”, step by step

crossword traces back through two separate lines of ancestry.

via English cross

StepLanguageWordMeaning
1EnglishcrossA geometrical figure consisting of two straight...
2Frenchcroixcross; a representation of a cross; the cross as...
3GermanKreuzcross; clubs; sharp
4SpanishCruzcross
5Portuguesecruzcross
6Italiancrocecross
7Latincruxwooden frame on which criminals were crucified,...
8Proto-Italic*kruks
9Proto-Indo-Europeansḱer-to caw, crow

via English Word

StepLanguageWordMeaning
1EnglishWordScripture; The Bible; The creative word of God;...
2EnglishworthHaving a value of; proper to be exchanged for;...
3Middle Englishworthto become
4Old Englishweorþworth, deserving; honoured, esteemed; worth,...
5Proto-Germanicwerþazworthy, valuable
6Proto-Indo-Europeanwert-to turn, to rotate
7Proto-Indo-Europeanwer-to burn; to cover, heed, notice; squirrel

Words derived from “crossword

Every word from Proto-Indo-European sḱer-