A glue <g/> is a special structure inserted into a corpus to tell Sketch Engine that two tokens, which would otherwise be displayed with a space in between, should actually be displayed without a space. Typically do and n’t will have glue between them to be displayed as don’t.

A glue does not have any other fuction, it is inserted for technical reasons only. It can, however, be used in CQL searches if there is a use case.