Other forms: backlogs
A backlog is the pile of work that has built up unfinished. Clear the backlog, a growing backlog, backlog of cases.
It grows when arrivals outpace completions, which sounds obvious and is the whole of queue theory: a system running near full capacity builds one at astonishing speed. Court and hospital backlogs are counted publicly. The word first meant a large log at the back of a fire, kept to burn slowly.
1nounbacklogThe pile of work that has built up unfinished.
“After the strike, the post office had a huge backlog of undelivered letters.”
backlog is an accumulation.
Back plus log, from the 1680s, first meaning a large log at the back of a fire. The figurative sense arrived in the 1880s.
From back + log. 1680s; originally a large log at the back of a fire. Figurative sense from 1880s, meaning "something stored up for later use". Possibly influenced by logbook as well.
Etymology from Wiktionary, CC BY-SA