MOS

MOS is an initialism that can refer to several concepts depending on the context. The most widely used senses are in electronics and in quality assessment, but the acronym also appears in military, entertainment, and other fields.

In electronics, MOS stands for metal-oxide-semiconductor. This refers to a class of devices built on a silicon substrate with an insulating oxide layer, forming MOS capacitors and, most prominently, metal-oxide-semiconductor field-effect transistors (MOSFETs). A MOSFET acts as a voltage-controlled switch or amplifier, with the gate controlling current between source and drain through a conducting channel. MOS devices come in enhancement-mode or depletion-mode varieties and in n-type or p-type forms, depending on the type of carriers. MOS technology underpins the vast majority of modern integrated circuits, enabling the high density and low power consumption characteristic of contemporary digital electronics.

Mean Opinion Score (MOS) is a subjective measure used to evaluate perceived audio or video quality. It is typically obtained by human raters who assign a score on a scale, often from 1 to 5, where higher values indicate better quality. MOS values are widely used in telecommunications, streaming, and conferencing to assess codecs, network performance, and quality of service.

Other uses include Military Occupational Specialty, the designation used by the U.S. Army and Marine Corps to categorize job specialties, and Ministry of Sound, a UK-based entertainment brand known for its record label and nightclub. The context usually clarifies which MOS is being referenced.