GEMARA. A WOMAN IS ACQUIRED. Why does he [the Tanna] state here, ‘A WOMAN IS ACQUIRED,’ Whilst elsewhere8 he teaches ‘A man may betroth’ [etc.]?9 — Because he wishes to state ‘MONEY’; and how do we know that money effects betrothal? By deriving the meaning of ‘taking’ from the field of Ephron:10 Here it is written: If any man take a wife;11 whilst there it is written: I will give thee money for the field: take it of me.12 Moreover, ‘taking’ is designated acquisition, for it is written, the field which Abraham acquired;13
9) Thus here too he should have stated: ‘A woman is betrothed.’ ‘Betroth’ in this sense, and as it is generally used in the  Talmud, is the first stage of marriage. A betrothed woman could not be freed without a divorce, though cohabitation was still forbidden. V. Glos. s.v. erusin. As far as practicable in this translation, ‘betrothed’ is employed to denote this first stage, and ‘marriage’ to denote the second (nissu'in), after which the couple may live together.