To adorn, to repair

There is a beautiful custom to hold night-time learning sessions on the eve of Shavuot. These are called "Tikkun", or more fully, "Tikkun Leyl Shavuot". What I realised this year for the first time is how the meaning of this word, its connotations, have changed.
Although a Tikkun is first described in the Zohar in mythical rather than practical terms, the practice of a Tikkun seems to have crystallised in 16th century kabbalistic circles around Joseph Caro (author of the Shulchan Arukh ("The laid table"), the classic compilation of Jewish Law, and Solomon Alkabetz, author of the Friday night hymn Lekha Dodi (see Daniel Matt, "Adorning the "Bride" on the Eve of the feast of weeks", in L. Fine, Judaism in Practice, 2007, pp. 74-80). The practice relies on the Zohar's description of Rabbi Shimon bar Yochai "plying Torah" during the night of Shavuot, on what is described as the eve of the wedding day between the Torah and God. The rabbi and his disciples are described as the "companions of the bride", who "adorn the bride" with jewels of Torah. In this context, Tikkun means adornment [of the bride], decoration.
Today we have a rather different understanding of what Tikkun means. If we think of a compound in Hebrew, we think of Tikkun Olam, repairing or healing the world. The concept of Tikkun Olam also goes back to the early modern Kabbalists of Safed, where the ritual and contemplative (and sometimes magical) practices of the kabbalistic initiates were believed to have cosmic powers to bring about the repair of the primordial cracked vessel of the world, and to collect the sparks of divine light from among the darkness. The kabbalists of old held many other Tikkun events during the year. The followers of Shabbetai Zevi were particularly fond of holding Tikkun Chatzot, midnight study sessions.
In modern times, the term has experienced a remarkable revival in the form of social action and activism. Perhaps symptomatically, the magazine Tikkun: a quarterly Jewish critique of politics, culture & society was first published in 1986.
It seems to me that this semantic move from the mystical and celebratory wedding symbolism to social activism is a healthy one. We are no longer confident that the future is a (wedding) party. We are more concerned with the urgent work of social as well as spiritual repair that needs to be done. And communal (rather than individual) study during the silence of the night can have a share in building community for social action.