Runners who are members of a UK Athletics affiliated running club are ‘attached’ or ‘affiliated’ runners.
Some clubs don’t have a UKA affiliation and some runners aren’t members of a club at all; if this is the case, then you are an ‘unattached’ or ‘unaffiliated’ runner. You can still enter your club name to on the entry form so that it’s listed in the results, but you won’t benefit from an affiliated entry rate.