handfasting
婚約
hand·fast, v. t. [imp. & p. p. handfasted; p. pr. & vb. n. handfasting.]
1. To pledge; to bind. [Obs.]
2. To betroth by joining hands, in order to permit cohabitation, before the formal celebration of marriage; in some parts of Scotland it was in effect to marry provisionally, permitting cohabitation for a year, after which the marriage could be formalized or dissolved. [Obs.]