So in school they teach you that 六月・ろくがつ is June, but at the library in one of my schools the display board clearly says that it's 水無月. I saw it just today as I walked past on the way to class.
Ha, I thought. How silly. June is the rainy season. That kanji literally means water-none-month! PREPOSTEROUS! Go home, library display board. You are clearly drunk.
But I was intrigued so I later googled 水無月 意味 由来 and good ol' Gogen Yurai Jiten 語源由来辞典 pops up with this:
「水の無い月と書くが、水が無いわけではない。水無月の「無」は、神無月の「な」と同じく「の」にあたる連体助詞「な」で、「水の月」という意味である。」
"The kanji is written "Month Without Water", but this does not necessarily mean "Without Water". The “without" 「無」 in "Month Without Water" is like the "without" 「無」 in "Month Without God", an "attributive particle" similar to "of" 「の」, making the meaning "Month of Water"."
OK, library display board. I apologize.