For a given car model, the trim level denotes which equipment and features are included as standard. A car buyer may add to this standard equipment with trim packages or individual options. The trim level with the least equipment/features is referred to as the "base model", and the trim level with the most equipment/features is referred to as "highest specification" or colloquially as "fully loaded". Differences between trim levels often consist of interior equipment (eg leather seats and reversing cameras), and cosmetic changes; however sometimes a trim level can include mechanical changes such as different engines, suspension or all-wheel drive systems.
Some car brands use a different car model for what could be instead considered a trim level, therefore the distinction between a model and trim level can vary between brands. For example, Volkswagen could choose to market the Golf GTi either as a standalone model, or as a trim level within the Golf model.