Difference between ‘tagging’ and ‘conjugating’ a fluorochrome to an antibody? The Wikipedia entry on fluorescence repeatedly states that “a fluorochrome must be tagged or conjugated to the antibody”. How is tagged or conjugated different? Is this a mistake or are these indeed different concepts?

Conjugated and tagged mean the same thing here, although I would advise against using tagged here.

In the context of antibodies, tagging means the addition of a (short) peptide sequence to a protein. Either to do something useful (degradation tag, HHHHHH-tag) or just as an epitope for an antibody.