In the context of security, attachment is the point in time when a security interest is created as between a debtor and creditor. The effect of attachment is that the security interest attaches to the asset which is the subject of the security, so as to give the creditor rights ("in rem") against the debtor.
Attachment can be distinguished from perfection. Perfection of a security interest typically requires a further step (for example, possession, registration or notice) to ensure that third parties (including other creditors) are subject to the security holder's interest in the secured asset.
For attachment in the context of enforcement of judgments and freezing orders, see attachment order ( www.practicallaw.com/8-107-6448) .