Most forum search engines deliberately ignore words less than 3 characters, allegedly to save space in the index (that's what PhpBB, the only one I have direct experience with, says but it's adjustable) – can't say they're totally wrong when, if asked to think of a 3-letter word, I'd say "are" or "and", but iI can confirm it does get really annoying much more often 😀
As for general purpose search engines… good luck, the google (apart from engaging in asshole design since give-or-take google+, which BTW had many technical merits) semi- or outright -officially stated they don't really try to index the whole accessible WWW, Bing is for porn and getting results related only to your location on page 2, DDG is low bullshit in UI but 98% a Bing frontend in content (and also known to be politically biased)…
Bing in 1000 words, note how bold is supposed to mean the matched part of the result:
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Another 1000 words, not for the prudish, btw remember the mid 2010s when 2/32GB windows tablets were cool?
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