Multi Select Picklist
From LongJump Support Wiki
Multi Select Picklists provide options in a field to make multiple selections from a list of values in a Global Picklist.
In the global picklist, although the labels for the enumerated values may contain commas, the enumerated values may not contain commas.
The orientation can be vertical or horizontal
- When displayed vertically, each label is shown on a separate line
- When displayed horizontally, the labels are shown on the same line, separated by commas
For Multi Select Picklist fields where the labels include commas, vertical orientation is the better choice