Apparently 開き means "opening" but お開き means "closure", which seems very counter intuitive. What is going on here? Are there any other similar cases in Japanese language?
2 Answers
Euphemism vs. Taboo Words
[婉曲語法]{えんきょくごほう} vs. [忌]{い}み[言葉]{ことば}
「[閉]{と}じる」 ("to close") is considered a taboo word for auspicious events such as a wedding party (even though the word itself is something we use without thinking on a daily basis). Thus, we choose to say 「お[開]{ひら}きにする」 to mean "bring (a happy event) to an end".
「閉じる」 is not the only 忌み言葉 that one needs to avoid using if one is giving a speech at a wedding party. Words with negative meanings in the particular context of "marriage" are to be avoided - [終]{お}わる (to end)、[出]{で}る (to leave)、[別]{わか}れる (to part), etc.
Other examples:
「[葦]{あし}」⇒「[葭]{よし}」: "Reed". 「あし」 sounds like 「[悪]{あ}し」("bad"), so let's call it 「よし」 so that it will sound like 「[良]{よ}し」("good")!
「[梨]{なし}」⇒「ありの[実]{み}」: "Pear". 「なし」 sounds like 「[無]{な}し」("nothingness", "non-existent"), so let's change it to 「ありの実」(literally, "fruit of the 'being/existing' kind")!
「スルメ」⇒「アタリメ」: "Dried squid". 「する/掏る」 means "to steal" and it can also mean "to lose" in gambling. That does not sound too positive so let's make it sound like "to win (money or object)" = 「[当]{あ}たる」!
(I chose the examples that I thought would be more interesting instead of the obvious ones used in weddings and funerals.)
I wouldn't touch upon the provenances of お開き as a mean to avoid 忌み言葉 - ominous word / phrase as they were detailed by other users, and most of today's people wouln't give any thought about it. I wonder how many Japanese would associate it with 忌み言葉 today unless they are oct or nonagenarians.
I just would like to say お開き is very popular word which is used in both business and social life as in;
これでお開きにしましょう - Let's finish the meeting.
ぼつぼつお開きです - The party will end soon.
では部長、お開きの言葉をお願いします Well, Director, would you give a closing remark of the get-together?
まだお開きは早いんじゃないの？ Isn't it too early to close the party?
An alternative to お開き is 締め (tightening) as in;
"ではこの辺りで締めましょう - Now, let's conclude the discussion (meeting) at this poit."
"会長、締めをお願いします - Chairman, please wrap up the gathering."
It is customary to wrap up a celebration party such as a New Year and Year-end party and any get-together by performing "三本 (or 一本)締め" by clapping hands of all perticipants thrice (or once) in accord by the lead of party leader in Japanese society.
「終わる」「閉じる」を嫌って言い換えた言葉。もと「さる」「帰る」の忌詞(いみことば)。語源由来辞典 also says会合や宴会、特に祝宴で「終わり」「散会(散る)」「閉会(閉じる)」という不吉な表現を避けるために用いられる。本来は、武士が「退却する」「退陣する」という意味で使った忌み言葉。そこから、近世には「帰る」「去る」という意味が生じ、明治以降「散会」「閉会」の意味で「お開き」が用いられるようになった