that that /ðæt/

conjunction

1. () Introduces a subordinate clause  ( that )
   introduces a subordinate clause
   

pronoun

1. () Referring to a specific object, individual, or concept, often for emphasis or differentiation.  ( that )
   Referring to a specific object, individual, or concept, often for emphasis or differentiation.
   
2. () Used to specify one particular thing from another.  ( that )
   Used to specify one particular thing from another.