From Longman Dictionary of Contemporary Englishby a long wayby a long wayby a large amount He was the best in the group by a long way. → way
Examples from the Corpus
by a long way• He plays both but his preference, and by a long way, is for gaelic football.• In the home market, it led the field by a long way, with 4,337,487 units sold.• It is by a long way his preferred title when he refers to himself.• It is, by a long way, the greatest test yet of whether he is up to the job.• The expense allowances they received often failed, sometimes by a long way, to cover the costs they had to meet.• Moreover, the pretty paper kites in the clear blue skies still outnumber the documentary versions by a long way.• And before they went there I thought they would, by a long way. 