*delayed* is usually a precursor to cancelled
It used to be, but more often that not it means just a minor delay now. I think the software was changed to display 'delayed' whenever a train is overdue at a reporting point by even a small amount of time - whereas before I think it was only displayed if it was over 10 minutes late leaving its origin station.
It can be misleading - for example, the 09:27 Paddington to Oxford was showing delayed for the whole journey, but actually left just now only five minutes late. With pathing allowances/padding etc, it should be back on time by Reading, and certainly at Didcot where it sits for seven minutes!