Concatenate means to link together in a series or chain, or simplistically, to place one thing right after another.
Here's how it might look on a Keystroke report:
Concatenated: Bob Smith
Not Concatenated: Bob Smith
The first name field in the non-concatenated version has a Width of 10 characters.
The first name in the concatenated version is only as wide as the text in the field. Note that there's a space between the first and last name in the concatenated version. If the space out was left out, it would look like this: BobSmith.
There are two ways to concatenate fields on a report or label. Both ways let you insert spaces between fields. Each gives you different additional forms of control over the fields.
Variables - allows for the use of formula Operators and Functions.
Width = -2 - allows for the Flags and Decimal formatting on individual fields.
See:
Report/Label Editor Contents