An Environmental suit or EV suit is a specialised type of clothing used to project the wearer from hazards and maintain life-support in inhospitable environments.
EV suits can be used for a variety of tasks; for extravehicular activities, to explore a non-class M environments (or dependent on your species whatever environments might usually cause you harm) or to work in hazardous areas protected from various forms of chemicals and radiations.
There are a number of specialised EV suits, with magnetic boots to walk on the hull of a starship or a small propulsion unit to allow independent travel a short distance into open space. Anthropological isolation suits seem to stem from EV suit technologies sealing a researcher off from their unsuspecting study subjects.
History of EV suits
EV suits used by Earth Starfleet in the 22nd century were a bronze color utilizing a soft body suit with more solid components where necessary. These EV suits had magnetic boots and had various safety measures such as the ability to share an oxygen supply if one was damaged or lost.
The suits were generally emblazoned with the mission patch of the starship they were assigned to and key crew members had their own tailored suits whilst other personnel utilized shared suits. MACOs also had their own style of suit presumably designed to be more effective in combat situations.
By the 2260s Starfleet began to use new Silver suits which consisted of mostly of a flexible form fitting body suit with a tall helmet. Later in the decade Starfleet began to use Life support belts, a type of personal force field, however these seemed to have been phased out in later years as Starfleet returned to more solid suit designs. (TOS episode: The Tholian Web and The Animated Series)
By the 24th century Starfleet was using a white EV suit with a body suit and solid components which were of form fitting design to fit the user to without restrictions of movement and vision.
Benjamin Sisko, Kira Nerys and Worf wore environmental suits in 2374 when they beamed down to Jeraddo. They later wore them again when the artificial gravity and life support in parts of Deep Space 9 was interrupted by Obanak Keelen's inhabitation by the Pah-wraiths. (DS9 video game: The Fallen)
Geordi La Forge had a great dislike for the Starfleet environmental suit even with the modifications that had been introduced after his time at Starfleet Academy. The suit was known as the standard extravehicular work garment (or SEWGs) in Starfleet-speak. (TNG novel: A Time to Sow)