(US, alternative in Canada) A system, policy or understanding based on trust in the honesty, honor, or integrity of others.

plural of operating system

A communication system in which multiple users share a common channel in a way that can lead to conflicts.

A system of beliefs.

plural of contention system

plural of belief system

(physiology) The parts of an animal body comprising the heart, blood vessels (arteries, veins, and capillaries), and blood, which circulate the blood around the body.

(medicine) A blood group system, the second most important after the ABO system, and important in human blood transfusion, whereby blood types are classified according to the presence ("positive") or absence ("negative") of potentially over 50 antigens, of which the most commonly referenced is RhD.

In Latin, the three perfect tenses: perfect, future perfect, and pluperfect or past perfect, as contrasted with the present system: present, future, and imperfect. A verb in the perfect system indicates an action that has completed.

In Latin, the three simple tenses: present, future, and imperfect, as contrasted with the perfect system, the three perfect tenses: perfect, future perfect, and pluperfect. Verbs in the present system tend to indicate an action that has not completed.