It links a .DLG file to a specific .ITM file to enable it to be interactable or conversable. Such as the Modron Cube.
The first column defines the item resref.
The LABEL column defines the string reference for the button label on the item description screen. 4251 is commonly used for writing "Use" on the button.
The FILE column defines the dialog resref that is used when you click on the item's interactable button.
The NAME column defines the string reference to the name that is used when the conversation takes place.

In PSTEE we have:

2DA V1.0
-1
            LABEL   FILE        NAME
BLADEIM     4251    DBLADEIM    50570
BSPHERE     4251    DBSphere    61580
CELESTI2    4251    DCELEST     59854
CHEATS      4251    DCHEATS     47141
CIRCLEZ     4251    DCIRCLEZ    30406
CODEXI      4251    DCODEXI     48287
COPEARC     4251    DCOPEARC    46722
CUBE        4251    DCUBE       19329
DBOX        4251    MBOX        50811
DOLL        4254    DDOLL       19325
EAXE        4251    DEBLADE     53777
EDAG        4251    DEBLADE     53777
EFIST       4251    DEBLADE     53777
EHAM        4251    DEBLADE     53777
EMACE       4251    DEBLADE     53777
FINGER      4251    DFINGER     13338
FINNOTE     4251    DFINNOTE    50548
GDIARY      4251    DGDIARY     30414
ICTEETH     4251    DITEETH     61282
IPTEETH     4251    DITEETH     61282
JUSTFIER    4254    DJUSTFER    25988
LIMLIM      4254    DPETLIMI    48285
LINGASH     4254    DLINGASH    46720
M1CTEETH    4251    DITEETH     61282
M1PTEETH    4251    DITEETH     61282
M2CTEETH    4251    DITEETH     61282
M2PTEETH    4251    DITEETH     61282
M3CTEETH    4251    DITEETH     61282
M3PTEETH    4251    DITEETH     61282
MERTWYN     4254    DMHEAD      63692
MODMITE     4251    DRODMM      66958
MONJUG      4251    DMONJUG     48288
N1201       4251    DN1201      42307
PESTIL      4254    DPESTAL     30407
PORLENS     4251    DPORTAL     67154
P_JRNL      4251    DP_JRNL     50392
SCTRAP      4251    DSCTRAP     48286
SKJOURN     4251    DSKJOURN    61185
SKSCRAP     4251    DSKSCRAP    52588
SOHMIEN     4251    DSOHMIEN    50814
SOSTONE     4251    DSoStone    64664
SWORDOW     4251    DSWORDOW    50452
TOMBPLAN    4251    DTPLANS     -1
TRELON      4251    DTRELON     50815
UPORTAL     4251    DUPORTAL    65535
VKEY        4251    BEAD        46717
WSCROLL     4251    DWSCROLL    2210