Tags

Additional properties added to an element are called tags.  The concept of a tag is related to that of a stereotype.  For example, if a special type of block is created by defining a new stereotype on a profile, which inherits from the SysML block superclass, then an attribute can be assigned to the new type of block. 

An example of a new stereotype

When a block of the new type is placed on a block definition diagram, for example, that block will possess a tag defined by the attribute on the stereotype.  Tags are generally not displayed in a compartment of the block when the block is visualized on a block definition diagram, however.

Example of a Block with the new stereotype applied

Example of the newly-created Tag

Reference:

Friedenthal, S., Moore, A., & Steiner, R. (2012) A Practical Guide to SysML. Waltham, MA: Morgan Kaufmann. pg. 97.