Stasis is a concept that denotes the suspension of the passage of time, whether by biological means (deep sleep/hypersleep) or physical means, called stasis fields.
A stasis field is a region where a stasis process is in effect. Stasis fields in fictional settings often have several common characteristics. These include infinite or near-infinite rigidity, making them "unbreakable objects", and a perfect or nearly-perfect reflective surface. A device commonly known as the hypersleep chamber is used to establish this region. When the device is deactivated, the stasis field collapses; that is, the stasis effect ends.
Time is often suspended in stasis fields. Such fields will thus have the additional property of protecting non-living materials from deterioration. This time dilation can be, from an in-universe perspective, absolute, so that something thrown into the field, has the field triggered, and after any length of time reactivated, would fly out as if nothing had happened. Such fields are capable of allowing materials as well as living beings to survive for thousands or millions of years beyond their normal lifetimes.
The primary use of stasis fields is essentially the same as suspended animation: to let passengers and cargoes (normally of spacecraft) avoid having to experience extremely long periods of time by "skipping over" large sections of it. They may also be used as protection against the effects of extreme acceleration.