Maintenance glossary

Reviewed by José Luis Pérez on 2026-11-13

These are the maintenance terms used in the tools and guides on this site, defined in plain words. They describe how the terms are used here; they are not technical or legal advice.

Asset: A piece of equipment that a team maintains and keeps a record for, such as a compressor or a forklift.
Asset ID: A stable identifier for one piece of equipment, ideally the same one written on the machine. It is used on work orders and in the equipment's maintenance log so every record points to the same machine.
Calendar-based maintenance: Maintenance triggered by the passing of time: a task is due on a date, however much the equipment ran. See Calendar-based vs meter-based maintenance.
CMMS: Computerized maintenance management system: software that keeps equipment, work orders, schedules and maintenance history in one place.
Date based on completion: A due date counted from the day the previous work was actually finished. If work is done late, every following date shifts later too. See Fixed due dates vs dates based on completion.
Equipment maintenance log: The dated record of the work done on one piece of equipment: what was done, who did it and what they observed. Also called a maintenance history. See Equipment maintenance log.
Fixed due date: A due date set in advance from the first due date. It does not move when work is done early or late, which keeps a steady rhythm and makes late work easy to see. See Preventive maintenance scheduler.
ICS file: A standard calendar file (.ics) that most calendar apps can import. Each due date in it becomes a calendar event.
Inspection checklist: A list of items to check during a job, each marked OK, Needs attention or N/A. It records what was checked; it does not certify that equipment is safe.
Maintenance plan: What should happen next on a piece of equipment and when. It is different from the maintenance history, which records what actually happened. See How to keep an equipment maintenance history.
Meter-based maintenance: Maintenance triggered by measured use, such as operating hours, cycles or distance: a task is due when a reading is reached. See Calendar-based vs meter-based maintenance.
On-time completion: The share of scheduled maintenance tasks completed by their due date in a period. It measures punctuality; it does not measure breakdowns or savings.
Preventive maintenance: Maintenance planned in advance and done at set dates or usage readings, instead of after a failure. The manufacturer's manual says which tasks and how often. See Preventive maintenance scheduler.
Work order: The document for one maintenance job: which equipment, what to do, who does it and by when, with space to record that it was done. See Work order example.