Eternity vs. Sempiternity

Eternity, in common parlance, means infinite time that never ends (or the quality, condition or fact of being eternal). Classical philosophy, however, defines eternity as what exists outside time - as in describing supernatural beings and forces, whereas sempiternity corresponds to the infinitely temporal, non-metaphoric definitions, as recited in requiem prayers for the dead.

Enduring forever; eternal.

infinite or unending time

Existence within time but infinitely into the future, as opposed to eternity, understood as existence outside time.

Time without beginning or end; infinite time.

(literary) Eternity; a seemingly everlasting period of time.

The state or quality of being eternal.

Future duration without end; the relation or state of being sempiternal.

The timeless state following death.

the property of being perpetual (seemingly ceaseless)

The afterlife; immortality.

A very long or seemingly endless time

(uncountable) Existence without end, infinite time.

Existence outside of time.

(countable) A period of time which extends infinitely far into the future.

(metaphysical) The remainder of time that elapses after death.

A comparatively long time.

Infinite duration, without beginning in the past or end in the future; also, duration without end in the future; endless time.

Condition which begins at death; immortality.

time without end

a state of eternal existence believed in some religions to characterize the afterlife

a seemingly endless time interval (waiting)