Lookup context is a limiting condition for the allowed values of a lookup field, based on the value of a controlling, i.e., context field. The context field can be a field of the same object or the header object, and it has to be included in the page layout.

For example, if Account is set up as the context for Contact lookup and you have selected ABC Inc. in the Account field, the Contact result set will display only those contacts that are linked to the account ABC Inc. Another example is where the context for Technician lookup field in Work Order is the City field, to display only those technicians whose city is the same as the Work Order city.

The value of the context field and the value of the Matching Field in the lookup object record(s) should match exactly for the record(s) to be included in lookup search results. The requirement for context match can be allowed to be overridden by the end user in SFM Delivery, by checking the Override Context checkbox in SFM Designer.